1 files changed, 36 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..db3f19f8ac 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 IN GITHUB, GUIDES ARE PUBLISHED IN 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 in 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.
 
@@ -195,7 +195,7 @@ 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 +207,7 @@ 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 +289,12 @@ $ 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 +325,12 @@ 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
@@ -393,7 +404,7 @@ 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 +566,23 @@ $ 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: