Does not work with ember-data 3.x

[jacobq]

This is probably obvious since the last commit is several years old, but this addon does not appear to work with ember(-data) 3.x. I get an error like this:

Uncaught Error: Could not find module `ember` imported from `ember-cli-test-model-waiter/instance-initializers/test-model-waiter` at serve://dist/assets/vendor.js, line 252