Update README and version to 4.0.1.

Merge branch 'CityBaseInc-ruby_3'

Version 4.0.0

* CityBaseInc-ruby_3:
  Going to go to version 4.
  Adding splat for kwargs

Merge branch 'proton-lookup_by_array'

Version 3.7.0

* proton-lookup_by_array:
  lookup by array

Merge branch 'disable_autoloading'

Version 3.6.0

* disable_autoloading:
  Explicitly load all resources, do not use the autoloader

Fix compatibility with rspec-mocks 3.10.1

Version 3.5.0

Merge branch 'MityaLiu-master'

* MityaLiu-master:
  Updated versions of sqlite3 and rails.

Merge branch 'fix_collection_method_on_reflection'

* fix_collection_method_on_reflection:
  EnumerationReflection needs to implement "collection?"

Merge branch 'rails_5.2_support'

* rails_5.2_support:
  Implement support for Rails 5.2

Implement "all_except" method.

Release 3.2.0

Add association_class method to reflection