Working on ring layout

* Added bootstrap CSS and JS and Underscore to help with functionality.
Bootstrap is likely not necessary for this stage, but it will be when it
is time to add Popovers to the cards. Underscore may not be necessary
either - will remove it turns out to be useless.
* Set ring styles to display a circular border, center the ring, and
shape the cards as circles.
Add invited cards in to card stack

* Repositioned the invited cards in to the card stack. A much better
visual ensues.