Pass on arguments passed to the FeatureConstrainer

All arguments passed to the `FeatureConstrainer` will be passed on to
the `Feature.enabled?` check.

config/routes/api.rb

-constraints(::Constraints::FeatureConstrainer.new(:graphql, nil, true)) do
+constraints(::Constraints::FeatureConstrainer.new(:graphql, default_enabled: true)) do
   post '/api/graphql', to: 'graphql#execute'
   mount GraphiQL::Rails::Engine, at: '/-/graphql-explorer', graphql_path: '/api/graphql'
 end

lib/constraints/feature_constrainer.rb

@@ -2,14 +2,14 @@
 
 module Constraints
   class FeatureConstrainer
-    attr_reader :feature, :thing, :default_enabled
+    attr_reader :args
 
-    def initialize(feature, thing, default_enabled)
-      @feature, @thing, @default_enabled = feature, thing, default_enabled
+    def initialize(*args)
+      @args = args
     end
 
     def matches?(_request)
-      Feature.enabled?(feature, @thing, default_enabled: true)
+      Feature.enabled?(*args)
     end
   end
 end

spec/lib/constraints/feature_constrainer_spec.rb

+require 'spec_helper'
+
+describe Constraints::FeatureConstrainer do
+  describe '#matches' do
+    it 'calls Feature.enabled? with the correct arguments' do
+      expect(Feature).to receive(:enabled?).with(:feature_name, "an object", default_enabled: true)
+
+      described_class.new(:feature_name, "an object", default_enabled: true).matches?(double('request'))
+    end
+  end
+end