README.md in dir_model-0.3.3 vs README.md in dir_model-0.3.4

@@ -89,9 +89,13 @@
   end
 
   def image
     source_model.zone
   end
+
+  def image_extension
+    '.png'
+  end
 end
 
 fixture_models = [
   OpenStruct.new({
     id: 42,