message: Update README to explain a bit about how this addon works
diff: <iframe src="https://xd.adobe.com/embed/fc8c4920-5374-4476-5ec6-ba629f92f862-8abd/screen/69e7b00f-4d1d-4dc7-a88d-bb4fb23e4bd6/Zoom-in-Plane-1-" frameborder="0" allowfullscreen></iframe>
  -boxel
  -==============================================================================
  +# boxel
  +The repository provides an Ember Addon allowing usage of the Ember component library for the Boxel Design System.
  +
  +It consists of several parts:
  +1. The Boxel Design System Components and their documentation
  +2. Various prototypes using the design system
  +3. Miscellaneous components that will eventually be moved
  +
  +## Design system components
  +All components in `/addon/components` will be used in whatever apps consume the design system. Each component folder consists of several parts:
  +- `index.hbs` & `index.js`: The template and javascript for the component
  + - *Note:* Unlike a usual Ember addon, these files are automatically reexported in whatever app consumes the addon. So there is no need to handle that on your own.
  +- `index.css`: The pure CSS styles associated with the component. This file will automatically be added to the consuming app as well
  +- `usage.hbs` & `usage.js`: A standardized way to document and experiment with the designs of each component. All usage files will automatically show up in the components list in `/docs` in the dummy app. Utilizes chrislopresto/ember-freestyle
  + - *Note:* These files are automatically stripped out of any production build
  +
  +## Prototypes
  +The prototypes are there to exercise in context various aspects of the design system.
  +
  +## Miscellaneous Components
  +There are many components that are specific to a certain prototype or will eventually be moved to other repos, like the main Cardhost app.
  +## Running the dummy app
  +
  +```sh
  +ember serve
  +```
  +
  +Then browse to http://localhost:4200/
  +## Running tests
  +
  +```sh
  +ember test
  +```
  +
  +#### Thumbnails
  Generating multiple image sizes / thumbs from
  `/public/media-registry/covers/`:
  