Change way of finding policy for scopes

[phyrog]

Should fix #28. It's not as straight forward as it could be, but unfortunately Pundit only recognizes model_name, which is not defined by Sequel.

[codecov-io]

Codecov Report

Merging #29 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #29   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           6      6           
  Lines         315    344   +29     
=====================================
+ Hits          315    344   +29

Impacted Files	Coverage Δ
lib/graphql-pundit/instrumenters/scope.rb	100% <100%> (ø)	⬆️
spec/graphql-pundit/instrumenters/scope_spec.rb	100% <100%> (ø)	⬆️

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[eugenk]

But model_name is defined by ActiveModel and there is an :active_model plugin for sequel if I remember correctly.

[phyrog]

Hm, but I wouldn't want to force someone to use the active_model plugin just for this, so I think handling model in this code is fine.

[eugenk]

When I include this in the backend, I get:

  1) Rest::RepositoriesController successful action: index
     Failure/Error: old_resolve.call(resource, arguments, context)

     NameError:
       uninitialized constant RepositoryPolicy::Scope::Scope
     # graphql-pundit/lib/graphql-pundit/instrumenters/scope.rb:43:in `find_scope'

[eugenk]

Please add a comment why we do this.

[phyrog]

e4f9187 should have fixed the backend error. I think it was some strange interplay with some lazy code (the lambda).

[eugenk]