private method doesn't work for singleton methods defined this way
Fixed problem where `1.day.eql?(1.day)` is false

This fixes:
    1.second.eql?(1.second) #=> false

The new `eql?` requires that `other` is an `ActiveSupport::Duration`.
This requirement makes `ActiveSupport::Duration`'s behavior consistent
with other numeric types in Ruby.

    1.eql?(1.0) #=> false
    1.0.eql?(1) #=> false

    1.second.eql?(1) #=> false (was true)
    1.eql?(1.second) #=> false

    { 1 => "foo", 1.0 => "bar" }
    #=> { 1 => "foo", 1.0 => "bar" }

    { 1 => "foo", 1.second => "bar" }
    # now => { 1 => "foo", 1.second => "bar" }
    # was => { 1 => "bar" }

And though the behavior here hasn't changed, for reference:

    1 == 1.0 #=> true
    1.0 == 1 #=> true

    1 == 1.second #=> true
    1.second == 1 #=> true
Guides: minor typo fixed [ci skip]
Merge pull request #14652 from Emily/duration_eqls

Fixed problem where `1.day.eql?(1.day)` is false
Merge pull request #14653 from vdmgolub/patch-1

Guides: minor typo fixed in Asset Pipeline guide
Expand explanation of how to set secrets.yml. [ci skip]
upgrading section for 4.1 is no longer WIP. [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.