remove warn_if_using_mount_method!
Merge pull request #446 from jasl/remove-routes-deprecates

remove warn_if_using_mount_method!
Update tokens_controller.rb

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Merge pull request #447 from jasl/patch-1

Update tokens_controller.rb
dropping legacy doorkeeper_for and welcome doorkeeper_authorize!
Merge pull request #448 from jasl/new_filter_api

dropping legacy doorkeeper_for and welcome doorkeeper_authorize!
Undo behavior change on specs.

See
https://github.com/doorkeeper-gem/doorkeeper/pull/448/files#diff-403546b64759d2fcb933e8345a827403L2.
Update CHANGELOG. [ci skip]
README notifies that docs may differ per version.

[ci skip]
refactor model's modules by ActiveSupport::Concern and move them into models/concerns folder
clean up models validates
rename models' authenticate method
remove unnecessary model_name hacking in Application model
refactor model scopes concenrn