Import statement in docs

[analubarreto]

I'm pretty sure I should import something from somewhere before using Aviator.setRoutes, but you don't seem to have put it in the docs!

[ls-andrew-borstein]

@analubarreto you're right — anytime you want to use a method like Aviator.setRoutes or Aviator.navigate you should import it first, like

import Aviator from 'aviator';
import CampaignsTarget from 'route_targets/campaigns_target'

Aviator.setRoutes({
  '/campaigns': {
    target: CampaignsTarget,
    '/': 'index',
    '/add': 'add'
  }
});

Hope this helps!