This addon lets you set classes on the body like:
Whenever the above template is rendered, the <body>
tag will have class hello
added to it. When it's destroyed, the class is removed.
This works in both in-browser and in Fastboot. Fastboot support depends on https://github.com/ember-fastboot/fastboot/commit/20bbbc357b8183d0b2ca4463c5cb1dca5f7fdf8f).
ember install ember-set-body-class