1 files changed, 48 insertions, 8 deletions
diff --git a/guides/source/contributing_to_ruby_on_rails.md b/guides/source/contributing_to_ruby_on_rails.md
index 133ef58fd6..32d1e2c6e7 100644
--- a/guides/source/contributing_to_ruby_on_rails.md
+++ b/guides/source/contributing_to_ruby_on_rails.md
@@ -1,3 +1,5 @@
+**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.**
+
 Contributing to Ruby on Rails
 =============================
 
@@ -24,7 +26,7 @@ NOTE: Bugs in the most recent released version of Ruby on Rails are likely to ge
 
 ### Creating a Bug Report
 
-If you've found a problem in Ruby on Rails which is not a security risk, do a search in GitHub under [Issues](https://github.com/rails/rails/issues) in case it has already been reported. If you do not find any issue addressing it you may proceed to [open a new one](https://github.com/rails/rails/issues/new). (See the next section for reporting security issues.)
+If you've found a problem in Ruby on Rails which is not a security risk, do a search on GitHub under [Issues](https://github.com/rails/rails/issues) in case it has already been reported. If you are unable to find any open GitHub issues addressing the problem you found, your next step will be to [open a new one](https://github.com/rails/rails/issues/new). (See the next section for reporting security issues.)
 
 Your issue report should contain a title and a clear description of the issue at the bare minimum. You should include as much relevant information as possible and should at least post a code sample that demonstrates the issue. It would be even better if you could include a unit test that shows how the expected behavior is not occurring. Your goal should be to make it easy for yourself - and others - to replicate the bug and figure out a fix.
 
@@ -109,9 +111,7 @@ After applying their branch, test it out! Here are some things to think about:
 
 Once you're happy that the pull request contains a good change, comment on the GitHub issue indicating your approval. Your comment should indicate that you like the change and what you like about it. Something like:
 
-<blockquote>
-I like the way you've restructured that code in generate_finder_sql - much nicer. The tests look good too.
-</blockquote>
+>I like the way you've restructured that code in generate_finder_sql - much nicer. The tests look good too.
 
 If your comment simply says "+1", then odds are that other reviewers aren't going to take it too seriously. Show that you took the time to review the pull request.
 
@@ -173,6 +173,14 @@ $ git checkout -b my_new_branch
 
 It doesn't matter much what name you use, because this branch will only exist on your local computer and your personal repository on GitHub. It won't be part of the Rails Git repository.
 
+### Bundle install
+
+Install the required gems.
+
+```bash
+$ bundle install
+```
+
 ### Running an Application Against Your Local Branch
 
 In case you need a dummy Rails app to test changes, the `--dev` flag of `rails new` generates an application that uses your local branch:
@@ -195,7 +203,7 @@ Now get busy and add/edit code. You're on your branch now, so you can write what
 * Update the (surrounding) documentation, examples elsewhere, and the guides: whatever is affected by your contribution.
 
 
-TIP: Changes that are cosmetic in nature and do not add anything substantial to the stability, functionality, or testability of Rails will generally not be accepted.
+TIP: Changes that are cosmetic in nature and do not add anything substantial to the stability, functionality, or testability of Rails will generally not be accepted (read more about [our rationales behind this decision](https://github.com/rails/rails/pull/13771#issuecomment-32746700)).
 
 #### Follow the Coding Conventions
 
@@ -207,7 +215,7 @@ Rails follows a simple set of coding style conventions:
 * Use Ruby >= 1.9 syntax for hashes. Prefer `{ a: :b }` over `{ :a => :b }`.
 * Prefer `&&`/`||` over `and`/`or`.
 * Prefer class << self over self.method for class methods.
-* Use `MyClass.my_method(my_arg)` not `my_method( my_arg )` or `my_method my_arg`.
+* Use `my_method(my_arg)` not `my_method( my_arg )` or `my_method my_arg`.
 * Use `a = b` and not `a=b`.
 * Use assert_not methods instead of refute.
 * Prefer `method { do_stuff }` instead of `method{do_stuff}` for single-line blocks.
@@ -289,7 +297,12 @@ $ ruby -w -Itest test/mail_layout_test.rb -n test_explicit_class_layout
 The `-n` option allows you to run a single method instead of the whole
 file.
 
-##### Testing Active Record
+#### Testing Active Record
+
+First, create the databases you'll need. For MySQL and PostgreSQL,
+running the SQL statements `create database activerecord_unittest` and
+`create database activerecord_unittest2` is sufficient. This is not
+necessary for SQLite3.
 
 This is how you run the Active Record test suite only for SQLite3:
 
@@ -320,6 +333,12 @@ You can also run any single test separately:
 $ ARCONN=sqlite3 ruby -Itest test/cases/associations/has_many_associations_test.rb
 ```
 
+To run a single test against all adapters, use:
+
+```bash
+$ bundle exec rake TEST=test/cases/associations/has_many_associations_test.rb
+```
+
 You can invoke `test_jdbcmysql`, `test_jdbcsqlite3` or `test_jdbcpostgresql` also. See the file `activerecord/RUNNING_UNIT_TESTS.rdoc` for information on running more targeted database tests, or the file `ci/travis.rb` for the test suite run by the continuous integration server.
 
 ### Warnings
@@ -357,6 +376,10 @@ A CHANGELOG entry should summarize what was changed and should end with author's
 
 Your name can be added directly after the last word if you don't provide any code examples or don't need multiple paragraphs. Otherwise, it's best to make as a new paragraph.
 
+### Updating the Gemfile.lock
+
+Some changes requires the dependencies to be upgraded. In these cases make sure you run `bundle update` to get the right version of the dependency and commit the `Gemfile.lock` file within your changes.
+
 ### Sanity Check
 
 You should not be the only person who looks at the code before you submit it.
@@ -393,7 +416,7 @@ inside, just indent it with 4 spaces:
 
     class ArticlesController
       def index
-        respond_with Article.limit(10)
+        render json: Article.limit(10)
       end
     end
 
@@ -555,6 +578,23 @@ $ git push origin my_pull_request -f
 You should be able to refresh the pull request on GitHub and see that it has
 been updated.
 
+#### Updating pull request
+
+Sometimes you will be asked to make some changes to the code you have
+already committed. This can include amending existing commits. In this
+case Git will not allow you to push the changes as the pushed branch
+and local branch do not match. Instead of opening a new pull request,
+you can force push to your branch on GitHub as described earlier in
+squashing commits section:
+
+```bash
+$ git push origin my_pull_request -f
+```
+
+This will update the branch and pull request on GitHub with your new code. Do
+note that using force push may result in commits being lost on the remote branch; use it with care.
+
+
 ### Older Versions of Ruby on Rails
 
 If you want to add a fix to older versions of Ruby on Rails, you'll need to set up and switch to your own local tracking branch. Here is an example to switch to the 4-0-stable branch: