Added method `#eql?` to `ActiveSupport::Duration`, in addition to `#==`.

Currently, the following returns `false`, contrary to expectation:

    1.minute.eql?(1.minute)

Adding method `#eql?` will make this behave like expected. Method `#eql?` is
just a bit stricter than `#==`, as it checks whether the argument is also a
uration. Their parts may be different though.

    1.minute.eql?(60.seconds)  # => true
    1.minute.eql?(60)          # => false
Update RecordNotFound exception cases to include a message with the
Model that the Record was not found in.
Explain ERB space removal. [ci skip]
Use dynamic path for dummy app location in plugin's test_helper.rb
Don't autosave unchanged has_one through records
Make explicit 4.1 is being maintained by a special situation

[ci skip]
Merge pull request #16914 from untidy-hair/fix_plugin_dummy_path_error

Use dynamic path for dummy app location in plugin's test_helper.rb
Merge pull request #16790 from cirosantilli/explain-erb-space-removal

Explain ERB space removal.

[ci skip]
Added Responders docs, made Web Console docs more consistent. [ci skip]
Backwards compat for activerecord-deprecated_finders

Maintain compatibility for:
* ActiveRecord::Base#find(:all)
* ActiveRecord::Base#find(:first)
* ActiveRecord::Base#find(:last)
[guides] 4.2 release notes: added technical details for Adequate Record
Improve environment config templates consistency:

* Fix long lines;
* Use simple quotes for string literals when interpolation is not used.
Merge pull request #16841 from tjouan/environment-config-consistency

Improve environment config templates consistency
Merge pull request #16844 from zerothabhishek/master

[guides] 4.2 release notes: added technical details for Adequate Record
Specify dummy app's db migrate path in plugin's test_helper.rb
pg, correctly dump foreign keys targeting tables in a different schema.

Closes #16907.

[Matthew Draper & Yves Senn]
unify wording in Active Record CHANGELOG. [ci skip]
do not dump foreign keys for ignored tables.
ruby-head should be green

Ruby 2.2 is near to be released so we should support it properly
OMG mysql!