Migrate before_filter to before_action

[bronzdoc]

After Rails 5.1

All *_filter methods are now called *_action:
These methods were actually already deprecated in Rails 5.0, and Rails 5.1 removes support for *_filter usage, so you should be using *_action.

Before:

skip_before_filter :authenticate_user!
before_filter :authenticate_user!
after_filter :do_something

After:

skip_before_action :authenticate_user!
before_action :authenticate_user!
after_action :do_something