chore: remove sorted_set dependency (#1423)

Author: bf4

jsonapi-resources.gemspec

@@ -31,5 +31,4 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'activerecord', '>= 5.1'
   spec.add_dependency 'railties', '>= 5.1'
   spec.add_dependency 'concurrent-ruby'
-  spec.add_dependency 'sorted_set'
 end

lib/jsonapi/resource_fragment.rb

@@ -25,7 +25,7 @@ def initialize(identity, resource: nil, cache: nil, primary: false)
       @primary = primary
 
       @related = {}
-      @related_from = SortedSet.new
+      @related_from = Set.new
     end
 
     def initialize_related(relationship_name)

lib/jsonapi/resource_set.rb

@@ -180,7 +180,7 @@ def flatten_resource_tree(resource_tree, flattened_tree = {})
         flattened_tree[resource_klass][id][:resource] ||= fragment.resource if fragment.resource
 
         fragment.related.try(:each_pair) do |relationship_name, related_rids|
-          flattened_tree[resource_klass][id][:relationships][relationship_name] ||= SortedSet.new
+          flattened_tree[resource_klass][id][:relationships][relationship_name] ||= Set.new
           flattened_tree[resource_klass][id][:relationships][relationship_name].merge(related_rids)
         end
       end