14 files changed, 106 insertions, 25 deletions
diff --git a/guides/source/2_3_release_notes.md b/guides/source/2_3_release_notes.md
index 2302a618b6..52eeb4c2bc 100644
--- a/guides/source/2_3_release_notes.md
+++ b/guides/source/2_3_release_notes.md
@@ -8,7 +8,7 @@ Rails 2.3 delivers a variety of new and improved features, including pervasive R
 Application Architecture
 ------------------------
 
-There are two major changes in the architecture of Rails applications: complete integration of the [Rack](http://rack.rubyforge.org/) modular web server interface, and renewed support for Rails Engines.
+There are two major changes in the architecture of Rails applications: complete integration of the [Rack](http://rack.github.io/) modular web server interface, and renewed support for Rails Engines.
 
 ### Rack Integration
 
diff --git a/guides/source/3_0_release_notes.md b/guides/source/3_0_release_notes.md
index 2d7c06837b..fbb5690fa9 100644
--- a/guides/source/3_0_release_notes.md
+++ b/guides/source/3_0_release_notes.md
@@ -521,7 +521,7 @@ A large effort was made in Active Support to make it cherry pickable, that is, y
 These are the main changes in Active Support:
 
 * Large clean up of the library removing unused methods throughout.
-* Active Support no longer provides vendored versions of [TZInfo](http://tzinfo.rubyforge.org/), [Memcache Client](http://deveiate.org/projects/RMemCache/) and [Builder](http://builder.rubyforge.org/,) these are all included as dependencies and installed via the `bundle install` command.
+* Active Support no longer provides vendored versions of TZInfo, Memcache Client and Builder these are all included as dependencies and installed via the `bundle install` command.
 * Safe buffers are implemented in `ActiveSupport::SafeBuffer`.
 * Added `Array.uniq_by` and `Array.uniq_by!`.
 * Removed `Array#rand` and backported `Array#sample` from Ruby 1.9.
diff --git a/guides/source/3_1_release_notes.md b/guides/source/3_1_release_notes.md
index 485f8c756b..7626296e7d 100644
--- a/guides/source/3_1_release_notes.md
+++ b/guides/source/3_1_release_notes.md
@@ -173,7 +173,7 @@ The assets pipeline is powered by [Sprockets](https://github.com/sstephenson/spr
 
 ### HTTP Streaming
 
-HTTP Streaming is another change that is new in Rails 3.1. This lets the browser download your stylesheets and JavaScript files while the server is still generating the response. This requires Ruby 1.9.2, is opt-in and requires support from the web server as well, but the popular combo of nginx and unicorn is ready to take advantage of it.
+HTTP Streaming is another change that is new in Rails 3.1. This lets the browser download your stylesheets and JavaScript files while the server is still generating the response. This requires Ruby 1.9.2, is opt-in and requires support from the web server as well, but the popular combo of NGINX and Unicorn is ready to take advantage of it.
 
 ### Default JS library is now jQuery
 
diff --git a/guides/source/action_controller_overview.md b/guides/source/action_controller_overview.md
index 1735188f27..3d15319ca4 100644
--- a/guides/source/action_controller_overview.md
+++ b/guides/source/action_controller_overview.md
@@ -1078,7 +1078,7 @@ Rails keeps a log file for each environment in the `log` folder. These are extre
 
 ### Parameters Filtering
 
-You can filter certain request parameters from your log files by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log.
+You can filter out sensitive request parameters from your log files by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log.
 
 ```ruby
 config.filter_parameters << :password
@@ -1086,7 +1086,7 @@ config.filter_parameters << :password
 
 ### Redirects Filtering
 
-Sometimes it's desirable to filter out from log files some sensible locations your application is redirecting to.
+Sometimes it's desirable to filter out from log files some sensitive locations your application is redirecting to.
 You can do that by using the `config.filter_redirect` configuration option:
 
 ```ruby
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md
index ee8cf4ade6..486e7b80ff 100644
--- a/guides/source/active_record_querying.md
+++ b/guides/source/active_record_querying.md
@@ -659,6 +659,23 @@ FROM orders
 GROUP BY date(created_at)
 ```
 
+### Total of grouped items
+
+To get the total of grouped items on a single query call `count` after the `group`.
+
+```ruby
+Order.group(:status).count
+# => { 'awaiting_approval' => 7, 'paid' => 12 }
+```
+
+The SQL that would be executed would be something like this:
+
+```sql
+SELECT COUNT (*) AS count_all, status AS status
+FROM "orders"
+GROUP BY status
+```
+
 Having
 ------
 
@@ -1143,10 +1160,11 @@ Even though Active Record lets you specify conditions on the eager loaded associ
 However if you must do this, you may use `where` as you would normally.
 
 ```ruby
-Article.includes(:comments).where("comments.visible" => true)
+Article.includes(:comments).where(comments: { visible: true })
 ```
 
-This would generate a query which contains a `LEFT OUTER JOIN` whereas the `joins` method would generate one using the `INNER JOIN` function instead.
+This would generate a query which contains a `LEFT OUTER JOIN` whereas the
+`joins` method would generate one using the `INNER JOIN` function instead.
 
 ```ruby
   SELECT "articles"."id" AS t0_r0, ... "comments"."updated_at" AS t1_r5 FROM "articles" LEFT OUTER JOIN "comments" ON "comments"."article_id" = "articles"."id" WHERE (comments.visible = 1)
@@ -1154,7 +1172,19 @@ This would generate a query which contains a `LEFT OUTER JOIN` whereas the `join
 
 If there was no `where` condition, this would generate the normal set of two queries.
 
-If, in the case of this `includes` query, there were no comments for any articles, all the articles would still be loaded. By using `joins` (an INNER JOIN), the join conditions **must** match, otherwise no records will be returned.
+NOTE: Using `where` like this will only work when you pass it a Hash. For
+SQL-fragments you need use `references` to force joined tables:
+
+```ruby
+Article.includes(:comments).where("comments.visible = true").references(:comments)
+```
+
+If, in the case of this `includes` query, there were no comments for any
+articles, all the articles would still be loaded. By using `joins` (an INNER
+JOIN), the join conditions **must** match, otherwise no records will be
+returned.
+
+
 
 Scopes
 ------
diff --git a/guides/source/api_documentation_guidelines.md b/guides/source/api_documentation_guidelines.md
index 2a3bb4e34d..0a55e31818 100644
--- a/guides/source/api_documentation_guidelines.md
+++ b/guides/source/api_documentation_guidelines.md
@@ -13,7 +13,13 @@ After reading this guide, you will know:
 RDoc
 ----
 
-The Rails API documentation is generated with RDoc. Please consult the documentation for help with the [markup](http://rdoc.rubyforge.org/RDoc/Markup.html), and also take into account these [additional directives](http://rdoc.rubyforge.org/RDoc/Parser/Ruby.html).
+The [Rails API documentation](http://api.rubyonrails.org) is generated with RDoc.
+
+```bash
+  bundle exec rake rdoc
+```
+
+Resulting HTML files can be found and browsed at ./doc/rdoc directory. Just open index.html file in the browser and you're done.
 
 Wording
 -------
diff --git a/guides/source/asset_pipeline.md b/guides/source/asset_pipeline.md
index 559d3f5e7d..c81e9e58e3 100644
--- a/guides/source/asset_pipeline.md
+++ b/guides/source/asset_pipeline.md
@@ -794,7 +794,7 @@ For Apache:
 </Location>
 ```
 
-For nginx:
+For NGINX:
 
 ```nginx
 location ~ ^/assets/ {
@@ -816,7 +816,7 @@ compression ratio, thus reducing the size of the data transfer to the minimum.
 On the other hand, web servers can be configured to serve compressed content
 directly from disk, rather than deflating non-compressed files themselves.
 
-Nginx is able to do this automatically enabling `gzip_static`:
+NGINX is able to do this automatically enabling `gzip_static`:
 
 ```nginx
 location ~ ^/(assets)/  {
@@ -835,7 +835,7 @@ the module compiled. Otherwise, you may need to perform a manual compilation:
 ./configure --with-http_gzip_static_module
 ```
 
-If you're compiling nginx with Phusion Passenger you'll need to pass that option
+If you're compiling NGINX with Phusion Passenger you'll need to pass that option
 when prompted.
 
 A robust configuration for Apache is possible but tricky; please Google around.
@@ -920,7 +920,7 @@ cache forever. This can cause problems. If you use
 
 Every cache is different, so evaluate how your CDN handles caching and make sure
 that it plays nicely with the pipeline. You may find quirks related to your
-specific set up, you may not. The defaults nginx uses, for example, should give
+specific set up, you may not. The defaults NGINX uses, for example, should give
 you no problems when used as an HTTP cache.
 
 If you want to serve only some assets from your CDN, you can use custom
@@ -1024,12 +1024,12 @@ this passes responsibility for serving the file to the web server, which is
 faster. Have a look at [send_file](http://api.rubyonrails.org/classes/ActionController/DataStreaming.html#method-i-send_file)
 on how to use this feature.
 
-Apache and nginx support this option, which can be enabled in
+Apache and NGINX support this option, which can be enabled in
 `config/environments/production.rb`:
 
 ```ruby
-# config.action_dispatch.x_sendfile_header = "X-Sendfile" # for apache
-# config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for nginx
+# config.action_dispatch.x_sendfile_header = "X-Sendfile" # for Apache
+# config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX
 ```
 
 WARNING: If you are upgrading an existing application and intend to use this
@@ -1039,7 +1039,7 @@ and any other environments you define with production behavior (not
 
 TIP: For further details have a look at the docs of your production web server:
 - [Apache](https://tn123.org/mod_xsendfile/)
-- [Nginx](http://wiki.nginx.org/XSendfile)
+- [NGINX](http://wiki.nginx.org/XSendfile)
 
 Assets Cache Store
 ------------------
diff --git a/guides/source/caching_with_rails.md b/guides/source/caching_with_rails.md
index c652aa6a80..3e39ecdad2 100644
--- a/guides/source/caching_with_rails.md
+++ b/guides/source/caching_with_rails.md
@@ -28,7 +28,7 @@ config.action_controller.perform_caching = true
 
 ### Page Caching
 
-Page caching is a Rails mechanism which allows the request for a generated page to be fulfilled by the webserver (i.e. Apache or nginx), without ever having to go through the Rails stack at all. Obviously, this is super-fast. Unfortunately, it can't be applied to every situation (such as pages that need authentication) and since the webserver is literally just serving a file from the filesystem, cache expiration is an issue that needs to be dealt with.
+Page caching is a Rails mechanism which allows the request for a generated page to be fulfilled by the webserver (i.e. Apache or NGINX), without ever having to go through the Rails stack at all. Obviously, this is super-fast. Unfortunately, it can't be applied to every situation (such as pages that need authentication) and since the webserver is literally just serving a file from the filesystem, cache expiration is an issue that needs to be dealt with.
 
 INFO: Page Caching has been removed from Rails 4. See the [actionpack-page_caching gem](https://github.com/rails/actionpack-page_caching). See [DHH's key-based cache expiration overview](http://signalvnoise.com/posts/3113-how-key-based-cache-expiration-works) for the newly-preferred method.
 
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index 7a9e1beb23..a0f0738fba 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -120,7 +120,7 @@ numbers. New applications filter out passwords by adding the following `config.f
 
 * `secrets.secret_key_base` is used for specifying a key which allows sessions for the application to be verified against a known secure key to prevent tampering. Applications get `secrets.secret_key_base` initialized to a random key present in `config/secrets.yml`.
 
-* `config.serve_static_assets` configures Rails itself to serve static assets. Defaults to true, but in the production environment is turned off as the server software (e.g. Nginx or Apache) used to run the application should serve static assets instead. Unlike the default setting set this to true when running (absolutely not recommended!) or testing your app in production mode using WEBrick. Otherwise you won't be able use page caching and requests for files that exist regularly under the public directory will anyway hit your Rails app.
+* `config.serve_static_assets` configures Rails itself to serve static assets. Defaults to true, but in the production environment is turned off as the server software (e.g. NGINX or Apache) used to run the application should serve static assets instead. Unlike the default setting set this to true when running (absolutely not recommended!) or testing your app in production mode using WEBrick. Otherwise you won't be able use page caching and requests for files that exist regularly under the public directory will anyway hit your Rails app.
 
 * `config.session_store` is usually set up in `config/initializers/session_store.rb` and specifies what class to use to store the session. Possible values are `:cookie_store` which is the default, `:mem_cache_store`, and `:disabled`. The last one tells Rails not to deal with sessions. Custom session stores can also be specified:
 
@@ -729,7 +729,7 @@ Rails will now prepend "/app1" when generating links.
 
 #### Using Passenger
 
-Passenger makes it easy to run your application in a subdirectory. You can find the relevant configuration in the [passenger manual](http://www.modrails.com/documentation/Users%20guide%20Apache.html#deploying_rails_to_sub_uri).
+Passenger makes it easy to run your application in a subdirectory. You can find the relevant configuration in the [Passenger manual](http://www.modrails.com/documentation/Users%20guide%20Apache.html#deploying_rails_to_sub_uri).
 
 #### Using a Reverse Proxy
 
@@ -739,11 +739,11 @@ Many modern web servers can be used as a proxy server to balance third-party ele
 
 One such application server you can use is [Unicorn](http://unicorn.bogomips.org/) to run behind a reverse proxy.
 
-In this case, you would need to configure the proxy server (nginx, apache, etc) to accept connections from your application server (Unicorn). By default Unicorn will listen for TCP connections on port 8080, but you can change the port or configure it to use sockets instead.
+In this case, you would need to configure the proxy server (NGINX, Apache, etc) to accept connections from your application server (Unicorn). By default Unicorn will listen for TCP connections on port 8080, but you can change the port or configure it to use sockets instead.
 
 You can find more information in the [Unicorn readme](http://unicorn.bogomips.org/README.html) and understand the [philosophy](http://unicorn.bogomips.org/PHILOSOPHY.html) behind it.
 
-Once you've configured the application server, you must proxy requests to it by configuring your web server appropriately. For example your nginx config may include:
+Once you've configured the application server, you must proxy requests to it by configuring your web server appropriately. For example your NGINX config may include:
 
 ```
 upstream application_server {
@@ -769,7 +769,7 @@ server {
 }
 ```
 
-Be sure to read the [nginx documentation](http://nginx.org/en/docs/) for the most up-to-date information.
+Be sure to read the [NGINX documentation](http://nginx.org/en/docs/) for the most up-to-date information.
 
 #### Considerations when deploying to a subdirectory
 
diff --git a/guides/source/getting_started.md b/guides/source/getting_started.md
index d9619bbc21..e088abc150 100644
--- a/guides/source/getting_started.md
+++ b/guides/source/getting_started.md
@@ -623,6 +623,8 @@ method returns an `ActiveSupport::HashWithIndifferentAccess` object, which
 allows you to access the keys of the hash using either strings or symbols. In
 this situation, the only parameters that matter are the ones from the form.
 
+TIP: Ensure you have a firm grasp of the `params` method, as you'll use it fairly regularly. Let's consider an example URL: **http://www.example.com/?username=dhh&email=dhh@email.com**. In this URL, `params[:username]` would equal "dhh" and `params[:email]` would equal "dhh@email.com".
+
 If you re-submit the form one more time you'll now no longer get the missing
 template error. Instead, you'll see something that looks like the following:
 
@@ -739,6 +741,8 @@ database columns. In the first line we do just that (remember that
 `@article.save` is responsible for saving the model in the database. Finally,
 we redirect the user to the `show` action, which we'll define later.
 
+TIP: You might be wondering why the `A` in `Article.new` is capitalized above, whereas most other references to articles in this guide have used lowercase. In this context, we are referring to the class named `Article` that is defined in `\models\article.rb`. Class names in Ruby must begin with a capital letter.
+
 TIP: As we'll see later, `@article.save` returns a boolean indicating whether
 the article was saved or not.
 
diff --git a/guides/source/i18n.md b/guides/source/i18n.md
index 0eba3af6e8..8340d6807f 100644
--- a/guides/source/i18n.md
+++ b/guides/source/i18n.md
@@ -860,6 +860,24 @@ en:
       subject: "Welcome to Rails Guides!"
 ```
 
+To send parameters to interpolation use the `default_i18n_subject` method on the mailer.
+
+```ruby
+# user_mailer.rb
+class UserMailer < ActionMailer::Base
+  def welcome(user)
+    mail(to: user.email, subject: default_i18n_subject(user: user.name))
+  end
+end
+```
+
+```yaml
+en:
+  user_mailer:
+    welcome:
+      subject: "%{user}, welcome to Rails Guides!"
+```
+
 ### Overview of Other Built-In Methods that Provide I18n Support
 
 Rails uses fixed strings and other localizations, such as format strings and other format information in a couple of helpers. Here's a brief overview.
diff --git a/guides/source/migrations.md b/guides/source/migrations.md
index 6742c05946..31e314c69b 100644
--- a/guides/source/migrations.md
+++ b/guides/source/migrations.md
@@ -415,6 +415,29 @@ end
 removes the `description` and `name` columns, creates a `part_number` string
 column and adds an index on it. Finally it renames the `upccode` column.
 
+### Changing Columns
+
+Like the `remove_column` and `add_column` Rails provides the `change_column`
+migration method.
+
+```ruby
+change_column :products, :part_number, :text
+```
+
+This changes the column `part_number` on products table to be a `:text` field.
+
+Besides `change_column`, the `change_column_null` and `change_column_default`
+methods are used specifically to change the null and default values of a
+column.
+
+```ruby
+change_column_null :products, :name, false
+change_column_default :products, :approved, false
+```
+
+This sets `:name` field on products to a `NOT NULL` column and the default
+value of the `:approved` field to false.
+
 ### When Helpers aren't Enough
 
 If the helpers provided by Active Record aren't enough you can use the `execute`
diff --git a/guides/source/rails_on_rack.md b/guides/source/rails_on_rack.md
index 9053f31b8e..01941fa338 100644
--- a/guides/source/rails_on_rack.md
+++ b/guides/source/rails_on_rack.md
@@ -18,7 +18,7 @@ Introduction to Rack
 
 Rack provides a minimal, modular and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses in the simplest way possible, it unifies and distills the API for web servers, web frameworks, and software in between (the so-called middleware) into a single method call.
 
-- [Rack API Documentation](http://rack.rubyforge.org/doc/)
+* [Rack API Documentation](http://rack.github.io/)
 
 Explaining Rack is not really in the scope of this guide. In case you are not familiar with Rack's basics, you should check out the [Resources](#resources) section below.
 
diff --git a/guides/source/security.md b/guides/source/security.md
index 75d8c8e4c8..7e39986f8b 100644
--- a/guides/source/security.md
+++ b/guides/source/security.md
@@ -741,7 +741,7 @@ s = sanitize(user_input, tags: tags, attributes: %w(href title))
 
 This allows only the given tags and does a good job, even against all kinds of tricks and malformed tags.
 
-As a second step, _it is good practice to escape all output of the application_, especially when re-displaying user input, which hasn't been input-filtered (as in the search form example earlier on). _Use `escapeHTML()` (or its alias `h()`) method_ to replace the HTML input characters &amp;, &quot;, &lt;, &gt; by their uninterpreted representations in HTML (`&amp;`, `&quot;`, `&lt`;, and `&gt;`). However, it can easily happen that the programmer forgets to use it, so _it is recommended to use the [SafeErb](http://safe-erb.rubyforge.org/svn/plugins/safe_erb/) plugin_. SafeErb reminds you to escape strings from external sources.
+As a second step, _it is good practice to escape all output of the application_, especially when re-displaying user input, which hasn't been input-filtered (as in the search form example earlier on). _Use `escapeHTML()` (or its alias `h()`) method_ to replace the HTML input characters &amp;, &quot;, &lt;, &gt; by their uninterpreted representations in HTML (`&amp;`, `&quot;`, `&lt`;, and `&gt;`). However, it can easily happen that the programmer forgets to use it, so _it is recommended to use the SafeErb gem. SafeErb reminds you to escape strings from external sources.
 
 ##### Obfuscation and Encoding Injection