9 files changed, 93 insertions, 10 deletions
diff --git a/guides/source/action_controller_overview.md b/guides/source/action_controller_overview.md
index 3d15319ca4..57097ab146 100644
--- a/guides/source/action_controller_overview.md
+++ b/guides/source/action_controller_overview.md
@@ -1166,6 +1166,61 @@ end
 
 NOTE: Certain exceptions are only rescuable from the `ApplicationController` class, as they are raised before the controller gets initialized and the action gets executed. See Pratik Naik's [article](http://m.onkey.org/2008/7/20/rescue-from-dispatching) on the subject for more information.
 
+
+### Custom errors page
+
+You can customize the layout of your error handling using controllers and views.
+First define your app own routes to display the errors page.
+
+* `config/application.rb`
+
+  ```ruby
+  config.exceptions_app = self.routes
+  ```
+
+* `config/routes.rb`
+
+  ```ruby
+  get '/404', to: 'errors#not_found'
+  get '/422', to: 'errors#unprocessable_entity'
+  get '/500', to: 'errors#server_error'
+  ```
+
+Create the controller and views.
+
+* `app/controllers/errors_controller.rb`
+
+  ```ruby
+  class ErrorsController < ActionController::Base
+    layout 'error'
+
+    def not_found
+      render status: :not_found
+    end
+
+    def unprocessable_entity
+      render status: :unprocessable_entity
+    end
+
+    def server_error
+      render status: :server_error
+    end
+  end
+  ```
+
+* `app/views`
+
+  ```
+    errors/
+      not_found.html.erb
+      unprocessable_entity.html.erb
+      server_error.html.erb
+    layouts/
+      error.html.erb
+  ```
+
+Do not forget to set the correct status code on the controller as shown before. You should avoid using the database or any complex operations because the user is already on the error page. Generating another error while on an error page could cause issues.
+
 Force HTTPS protocol
 --------------------
 
diff --git a/guides/source/active_record_migrations.md b/guides/source/active_record_migrations.md
index 5a550d9e55..fd2125424b 100644
--- a/guides/source/active_record_migrations.md
+++ b/guides/source/active_record_migrations.md
@@ -434,6 +434,9 @@ 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.
 
+TIP: Unlike `change_column` (and `change_column_default`), `change_column_null`
+is reversible.
+
 ### Column Modifiers
 
 Column modifiers can be applied when creating or changing a column:
diff --git a/guides/source/asset_pipeline.md b/guides/source/asset_pipeline.md
index 2d1548f252..d984c5f27a 100644
--- a/guides/source/asset_pipeline.md
+++ b/guides/source/asset_pipeline.md
@@ -760,7 +760,7 @@ typical manifest file looks like:
 "digest":"12b3c7dd74d2e9df37e7cbb1efa76a6d"},"application-1c5752789588ac18d7e1a50b1f0fd4c2.css":{"logical_path":"application.css","mtime":"2013-07-26T22:56:17-07:00","size":1591,
 "digest":"1c5752789588ac18d7e1a50b1f0fd4c2"},"favicon-a9c641bf2b81f0476e876f7c5e375969.ico":{"logical_path":"favicon.ico","mtime":"2013-07-26T23:00:10-07:00","size":1406,
 "digest":"a9c641bf2b81f0476e876f7c5e375969"},"my_image-231a680f23887d9dd70710ea5efd3c62.png":{"logical_path":"my_image.png","mtime":"2013-07-26T23:00:27-07:00","size":6646,
-"digest":"231a680f23887d9dd70710ea5efd3c62"}},"assets"{"application.js":
+"digest":"231a680f23887d9dd70710ea5efd3c62"}},"assets":{"application.js":
 "application-723d1be6cc741a3aabb1cec24276d681.js","application.css":
 "application-1c5752789588ac18d7e1a50b1f0fd4c2.css",
 "favicon.ico":"favicona9c641bf2b81f0476e876f7c5e375969.ico","my_image.png":
diff --git a/guides/source/command_line.md b/guides/source/command_line.md
index 7e60f929a1..e283bcd0ef 100644
--- a/guides/source/command_line.md
+++ b/guides/source/command_line.md
@@ -294,6 +294,31 @@ Any modifications you make will be rolled back on exit
 irb(main):001:0>
 ```
 
+#### The app and helper objects
+
+Inside the `rails console` you have access to the `app` and `helper` instances.
+
+With the `app` method you can access url and path helpers, as well as do requests.
+
+```bash
+>> app.root_path
+=> "/"
+
+>> app.get _
+Started GET "/" for 127.0.0.1 at 2014-06-19 10:41:57 -0300
+...
+```
+
+With the `helper` method it is possible to access Rails and your application's helpers.
+
+```bash
+>> helper.time_ago_in_words 30.days.ago
+=> "about 1 month"
+
+>> helper.my_custom_helper
+=> "my custom helper"
+```
+
 ### `rails dbconsole`
 
 `rails dbconsole` figures out which database you're using and drops you into whichever command line interface you would use with it (and figures out the command line parameters to give to it, too!). It supports MySQL, PostgreSQL, SQLite and SQLite3.
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index a0f0738fba..3d6b2f79c6 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -552,7 +552,7 @@ development:
 $ echo $DATABASE_URL
 postgresql://localhost/my_database
 
-$ bin/rails runner 'puts ActiveRecord::Base.connections'
+$ bin/rails runner 'puts ActiveRecord::Base.configurations'
 {"development"=>{"adapter"=>"postgresql", "host"=>"localhost", "database"=>"my_database"}}
 ```
 
@@ -569,7 +569,7 @@ development:
 $ echo $DATABASE_URL
 postgresql://localhost/my_database
 
-$ bin/rails runner 'puts ActiveRecord::Base.connections'
+$ bin/rails runner 'puts ActiveRecord::Base.configurations'
 {"development"=>{"adapter"=>"postgresql", "host"=>"localhost", "database"=>"my_database", "pool"=>5}}
 ```
 
@@ -585,7 +585,7 @@ development:
 $ echo $DATABASE_URL
 postgresql://localhost/my_database
 
-$ bin/rails runner 'puts ActiveRecord::Base.connections'
+$ bin/rails runner 'puts ActiveRecord::Base.configurations'
 {"development"=>{"adapter"=>"sqlite3", "database"=>"NOT_my_database"}}
 ```
 
diff --git a/guides/source/engines.md b/guides/source/engines.md
index e7f024f1fc..4041cd7d55 100644
--- a/guides/source/engines.md
+++ b/guides/source/engines.md
@@ -94,7 +94,7 @@ including a skeleton structure that provides the following:
     ```
 
   * A file at `lib/blorgh/engine.rb`, which is identical in function to a
-  * standard Rails application's `config/application.rb` file:
+    standard Rails application's `config/application.rb` file:
 
     ```ruby
     module Blorgh
diff --git a/guides/source/getting_started.md b/guides/source/getting_started.md
index ea6c8cdd55..4a0600d02a 100644
--- a/guides/source/getting_started.md
+++ b/guides/source/getting_started.md
@@ -1873,7 +1873,7 @@ Then you make the `app/views/articles/show.html.erb` look like the following:
 <%= render @article.comments %>
 
 <h2>Add a comment:</h2>
-<%= render "comments/form" %>
+<%= render 'comments/form' %>
 
 <%= link_to 'Edit Article', edit_article_path(@article) %> |
 <%= link_to 'Back to Articles', articles_path %>
diff --git a/guides/source/layouts_and_rendering.md b/guides/source/layouts_and_rendering.md
index 5b75540c05..f00f7bca1b 100644
--- a/guides/source/layouts_and_rendering.md
+++ b/guides/source/layouts_and_rendering.md
@@ -308,7 +308,7 @@ TIP: This option should be used only if you don't care about the content type of
 the response. Using `:plain` or `:html` might be more appropriate in most of the
 time.
 
-NOTE: Unless overriden, your response returned from this render option will be
+NOTE: Unless overridden, your response returned from this render option will be
 `text/html`, as that is the default content type of Action Dispatch response.
 
 #### Options for `render`
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
index 6800e71a3c..1876959e03 100644
--- a/guides/source/upgrading_ruby_on_rails.md
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -146,7 +146,7 @@ If you use the cookie session store, this would apply to the `session` and
 
 Flash message keys are
 [normalized to strings](https://github.com/rails/rails/commit/a668beffd64106a1e1fedb71cc25eaaa11baf0c1). They
-can still be accessed using either symbols or strings. Lopping through the flash
+can still be accessed using either symbols or strings. Looping through the flash
 will always yield string keys:
 
 ```ruby
@@ -315,10 +315,10 @@ authors.compact!
 
 ### Changes on Default Scopes
 
-Default scopes are no longer overriden by chained conditions.
+Default scopes are no longer overridden by chained conditions.
 
 In previous versions when you defined a `default_scope` in a model
-it was overriden by chained conditions in the same field. Now it
+it was overridden by chained conditions in the same field. Now it
 is merged like any other scope.
 
 Before: