Added test to ensure that DescendantsTracker does not leak memory on singleton classes
Fix doc in Postgres database creation
add active model basics wip to guides/documents.yaml
support :unless_exist for FileCache
Add params option for button_to

The parameters are rendered as hidden form fields within the generated
form. This is useful for when a record has multiple buttons associated
with it, each of which target the same controller method, but which
need to submit different attributes.
Make the application name snake cased when it contains spaces

The application name is used to fill the `database.yml` and
`session_store.rb` files ; previously, if the provided name contained
whitespaces, it led to unexpected names in these files.

Since Shellwords.escape adds backslashes to escape spaces, the app_name
should remove them and replace any space with an underscore (just like
periods previously).

Also improve the assert_file helper to work with paths containing spaces
using String#shellescape.
Merge pull request #12606 from robin850/apps-with-spaces

Make the application name snake cased when it contains spaces
Fix order dependent tests
stop using `send` so that method privacy is respected and we get a small
perf increase
use the provided block to filter lists
do not search through the keys array twice
this should be private, no other instances of Root should call it
Try arel master

Conflicts:
	Gemfile
Let validates_inclusion_of accept Time and DateTime ranges

fixes 4.0.0 regression introduced in 0317b93c17a46d7663a8c36edc26ad0ba3d75f85
Merge pull request #12612 from amatsuda/amo_validates_inclusion_of_time_range_error

Let validates_inclusion_of accept Time and DateTime ranges
[ci skip] second parameter of asset-url is depricated
Merge pull request #12617 from skv-headless/master

[ci skip] second parameter of asset-url is deprecated
Fix the install task
Correct error in Utils.normalize_path that changed paths improperly
Merge pull request #12619 from Veraticus/fix_utils_normalize_path

Correct error in Utils.normalize_path that changed paths improperly