Missing docs for md-btn-submit

[tskarhed]

Code is not that advanced, but I think it should be mentioned in the documentation.

[mike-north]

Pull requests are welcome and appreciated :)

[tskarhed]

I can do that, but where do I find the files to modify?

[mike-north]

It's the dummy app in this addon https://github.com/mike-north/ember-cli-materialize/blob/master/tests/dummy/app/templates/buttons.hbs which references code snippets here https://github.com/mike-north/ember-cli-materialize/tree/master/tests/dummy/app/templates/snippets