Extending window in ember.js

How can I inject something that would be accessible in window.something

before dependencies would be loaded? I tried to do it in .ember-cli-build, but I don't know how to get access here to window

I want to do alias from another library

window.something = anotherLibrary

for now it could be even window.something = "something"

the most important thing to do it before other dependencies (because they waited for it and it doesn't exist)