unfactoring more module inclusion

lib/arel/algebra/relations/relation.rb

@@ -102,7 +102,6 @@ def each
       session.read(self).each { |e| yield e }
     end
 
-    module Operable
     def join(other_relation = nil, join_class = InnerJoin)
       case other_relation
       when String
@@ -169,8 +168,6 @@ def on(*predicates)
         join_class.new(relation1, relation2, *predicates)
       end
     end
-    end
-    include Operable
 
     def [](index)
       attributes[index]

spec/algebra/unit/relations/relation_spec.rb

@@ -23,7 +23,7 @@ module Arel
       end
     end
 
-    describe Relation::Operable do
+    describe 'Relation::Operable' do
       describe 'joins' do
         before do
           @predicate = @relation[:id].eq(@relation[:id])