Merge pull request #2633 from aaronfullerton/patch-1

Updated documentation wrt ejs exclusion

docs/src/pages/configurations/custom-webpack-config/index.md

@@ -87,6 +87,8 @@ Storybook uses the config returned from the above function. So, try to edit the
 -   first loader in the module.loaders (Babel loader for JS)
 -   all existing plugins
 
+> If your custom webpack config uses a loader that does not explicitly include specific file extensions via the `test` property, it is necessary to `exclude` the `.ejs` file extension from that loader.
+
 ## Full control mode + default
 
 You may want to keep Storybook's [default config](/configurations/default-config), but just need to extend it.