[MODEL] Changed the naming inheritance logic to use Elasticsearch::Model.settings

This patch removes the `Elasticsearch::Model.inheritance_enabled` method added
in b8455db, and changes the logic to use the `settings` for the module.

Related: elastic#332

Author: karmi

elasticsearch-model/lib/elasticsearch/model/naming.rb

@@ -75,7 +75,7 @@ def document_type=(name)
           def implicit(prop)
             value = nil
 
-            if Elasticsearch::Model.inheritance_enabled
+            if Elasticsearch::Model.settings[:inheritance_enabled]
               self.ancestors.each do |klass|
                 next if klass == self
                 break if value = klass.respond_to?(prop) && klass.send(prop)

elasticsearch-model/test/unit/naming_inheritance_test.rb

@@ -2,11 +2,11 @@
 
 class Elasticsearch::Model::NamingInheritanceTest < Test::Unit::TestCase
   def setup
-    Elasticsearch::Model.inheritance_enabled = true
+    Elasticsearch::Model.settings[:inheritance_enabled] = true
   end
 
   def teardown
-    Elasticsearch::Model.inheritance_enabled = false
+    Elasticsearch::Model.settings[:inheritance_enabled] = false
   end
 
   context "Naming module with inheritance" do
@@ -35,6 +35,16 @@ class Dog < ::Animal
       end
     end
 
+    class ::Cat < ::Animal
+      extend ActiveModel::Naming
+
+      extend  Elasticsearch::Model::Naming::ClassMethods
+      include Elasticsearch::Model::Naming::InstanceMethods
+
+      index_name "cats"
+      document_type "cat"
+    end
+
     should "return the default index_name" do
       assert_equal "test_bases", TestBase.index_name
       assert_equal "test_bases", TestBase.new.index_name
@@ -43,6 +53,9 @@ class Dog < ::Animal
     should "return the explicit index_name" do
       assert_equal "mammals", Animal.index_name
       assert_equal "mammals", Animal.new.index_name
+
+      assert_equal "cats", Cat.index_name
+      assert_equal "cats", Cat.new.index_name
     end
 
     should "return the ancestor index_name" do
@@ -63,6 +76,9 @@ class Dog < ::Animal
     should "return the explicit document_type" do
       assert_equal "mammal", Animal.document_type
       assert_equal "mammal", Animal.new.document_type
+
+      assert_equal "cat", Cat.document_type
+      assert_equal "cat", Cat.new.document_type
     end
 
     should "return the ancestor document_type" do