Bruno Vitorino

@Sufiyan The easiest way is to put your css and js in the web folder and include them in your twig templates with the tag <link href="{{ asset('bootstrap-theme/bootstrap-custom.css') }}" >

Very nice tip. thanks!

@Holliver, check if app\config\config.yml is correctly formatted, and no spaces mixed with tabs for indentation.

@poldas Thanks for your comment. Indeed the order of the library's inclusion is important and therefore we need to place bootstrap after jquery. Good catch! I had fixed it in my code but not here.
Indeed there seems to be a problem with the .css.map file, but it doesn't seem to occur when you run your application in production mode. Nevertheless I'll follow your comment and change it to the newest bootstrap version.
Cheers

I didn't have a good look at it yet, but it looks like the rendering of forms only adds class names to the forms. Therefore, I guess we still have to make the framework some how available in our application, as it's done in my method, through a bundle or some other solution.