allowing for extension of Scoping::Filter class

[amitsuryavanshi]

This change will allow someone to extend filtering classes like sonapiCompliable::Scoping::DefaultFilter, JsonapiCompliable::Scoping::Filter, JsonapiCompliable::Scoping::Sort, etc. for any additional or modified functionality.

[klobuczek]

+1
I have had similar problem in the past. Sometimes it is difficult to extend jsonapi_suite. Without such a refactoring you have to duplicate the entire apply_scoping method and thus become much more fragile and missing future extensions.

[richmolj]

What's an example of what you would do with a different filter class?

[amitsuryavanshi]

@richmolj as per our discussion on slack, I have updated the PR. Thanks.

[richmolj]

Released in 0.11.18