Allows to load custom themes and override areas defined by Ember Admin, which is a lazy loaded engine.
Install
ember install ember-admin-theme-manager
And in your parent app add the following:
Here selectedTheme
sets the active theme and mounts that once
Ember Admin has been laoded. This can be a dynamic value, so you
can use a select and change themes.
At the moment this doesn't support lazy loaded themes, because ember-engines don't support lazy loaded routeless engines yet, but the setup makes it possible once the support is there.