Only cache template digests if config.cache_template_loading

since ActionView::Resolver.caching is set to the same value as config.cache_template_loading
only cache template digests if config.cache_template_loading is not falsy
fixes issues #10752 and #10791
check class hierarchy with is_a? in PredicateBuilder.expand

add changelog entry for #11945
Merge pull request #11945 from Mik-die/polymorphic-decorator

check class hierarchy with is_a? in PredicateBuilder.expand
 #11803: Move Forbidden attributes description before show post section

[ci skip]
Remove gist link from the code

It is not good to include links in the code. These links can be in the
future outdated and nobody will upgrade they.

[ci skip]
Merge pull request #11805 from jetthoughts/11803_update_move_forbidden_exception_description_before_show

[Getting Started Guide] Move Forbidden attributes description before show post section [ci skip]
Merge pull request #11768 from cloudspace/cache_template_loading

Only cache template digests if !config.cache_template_loading
Improve CHANGELOG entry [ci skip]
Comply with current umask when generating new app:

  When creating a new application using the default rails generator
(`rails new my_app`), it will apply some permissions bypassing the
current process umask. The `bin' directory and any files inside it will
always be set a mode of 0755.

  This change removes the current umask bits from the mode applied by
the generator on the `bin' directory and its content.
Merge pull request #12048 from tjouan/app_generator-bin_perms-umask

Comply with current umask when generating new app
query the association rather than send the method for the association name
cache association reset calculation
remove intermediate variable
use consistent keys between cache get / set
Update Test::Unit to Minitest

Previous was misleading; current is more up to date.

[ci skip]
Merge pull request #12033 from alexaltair/patch-1

change reference of `Test::Unit` to `Minitest` [ci skip]
Mention the fast `test_sqlite3_mem` option in `RUNNING_UNIT_TESTS.rdoc` [ci skip]
Merge pull request #12053 from schuetzm/doc_sqlite3_mem

Mention the fast `test_sqlite3_mem` option in `RUNNING_UNIT_TESTS.rdoc` [ci skip]