Fix module namespace for initializer generator (jsonapi-rb#48)

Author: smaximov

lib/generators/jsonapi/initializer/initializer_generator.rb

@@ -1,7 +1,9 @@
-class InitializerGenerator < Rails::Generators::Base
-  source_root File.expand_path('../templates', __FILE__)
+module Jsonapi
+  class InitializerGenerator < Rails::Generators::Base
+    source_root File.expand_path('../templates', __FILE__)
 
-  def copy_initializer_file
-    copy_file 'initializer.rb', 'config/initializers/jsonapi.rb'
+    def copy_initializer_file
+      copy_file 'initializer.rb', 'config/initializers/jsonapi.rb'
+    end
   end
 end