Add form to validate ``Resources`` submitted.

https://github.com/madewithbytes/us_ignite/issues/138
Fix docstring description.
List tags in the ``Resource`` detail page.
Add functionality for users to submit ``Resources``.

https://github.com/madewithbytes/us_ignite/issues/138

Functionality is only available to registered users, after
creation redirects to the Resource detail page.

Uses a ``ModelForm`` for convenience, a URL or an asset
is required.
Add method to validate ``Resource`` ownership.

https://github.com/madewithbytes/us_ignite/issues/139
Amend Resource fixture, wrong keyword for the ``owner``.
Add mechanics to allow edition of ``Resources``.

https://github.com/madewithbytes/us_ignite/issues/139

The ``owners`` are the only users capable of editing a
``Resource``.