Expand explanation of how to set secrets.yml. [ci skip]
Merge pull request #14654 from Alamoz/secret_key

Expand explanation of how to set secrets.yml.
depend_on_asset is not required anymore on sprockets-rails 2.1.2
Add missing require so requiring `active_support/cache` works again.
Merge pull request #14667 from lucasmazza/require-per-thread-registry

Add missing require so requiring `active_support/cache` works again.
Avoid URI parsing

This parsing is unecessary once the Request object already has the
needed information.
Merge pull request #14665 from andrielfn/avoid-uri-parsing

Avoid URI parsing
The `source` option for `has_many => through` should accept String
values.

With the changes introduced by 16b70fddd4dc7e7fb7be108add88bae6e3c2509b
it was expecting the value to be a Symbol, while it could be also a
String value.
Merge pull request #14668 from laurocaetano/source_option_with_string_value

The :source option for has_many => through should accept String values.
add services: memcache to travis
Merge pull request #14671 from arthurnn/travis_memcache

add services: memcache to travis
Make the reflections cache work with strings as its keys.
No need to call `to_sym` on reflection name, since the cache now works
with strings with string keys.

Related #14668.
Make the aggregate_reflections cache work with strings as its keys.
Make sure the reflection test is passing a String to the reflection
cache.
Merge pull request #14675 from laurocaetano/make_reflection_caches_works_with_string_keys

Make reflection and aggregate_reflection caches work with string keys.
Remove extra collect call
Only call uniq on the conditional that actually needs it
Merge remote-tracking branch 'rails/master'