[ci skip] Update code snippets to latest master (initialization.md).
Also update the `server.run` example (Replace Mongrel with Puma).
Fix error for aggregate methods with select, see issue #13648
Merge pull request #14677 from JuanitoFatas/update-initialization-code-snippets

[ci skip] Update code snippets to latest master (initialization.md).
Merge pull request #11656 from emre-basala/xml_mini_test

Add tests to ActiveSupport:XmlMini to_tag method
Require action_controller before any other action_controller file

This will load properly the loading hooks.

Closes rails/sass-rails#205
Merge branch 'master' into rm-uuid-fixtures

Conflicts:
	activerecord/CHANGELOG.md
	activesupport/CHANGELOG.md
No need to call send
Merge branch 'rm-uuid-fixtures'
Remove warning of unused variable
Add after_commit/after_rollback to callback list

Adding after_commit/after_rollback to list of callbacks in order helps
explain the callback order as well as making it consistent with the API
docs at http://api.rubyonrails.org/classes/ActiveRecord/Callbacks.html
[ci skip] Remove false documentation
Merge pull request #14695 from akshay-vishnoi/doc_changes

[ci skip] Remove false documentation
Merge pull request #14694 from heironimus/callback_guide

Add after_commit/after_rollback to callback list
Merge pull request #12829 from iantropov/issue_insert_via_hmt_scope_3548

Fix insertion of records for hmt association with scope

Conflicts:
	activerecord/CHANGELOG.md
remove dead code
eagerly build the relation object
eagerly build the bind map
eagerly build the cacheable query builder
fix ivar names and add reader methods
stop caching the class on the statement cache object