If all of a user's shows (accounts) have moved to the new Feeder UI ... show them a modal and redirect them there.
It's always possible that a user will have some shows in Publish and some in Feeder. That should be fine - this only shows up once all your shows have moved.
Needs PRX/cms.prx.org#623.
Related to https://github.com/PRX/id.prx.org/pull/363, but I don't think it needs that to deploy.
If all of a user's shows (accounts) have moved to the new Feeder UI ... show them a modal and redirect them there.
It's always possible that a user will have some shows in Publish and some in Feeder. That should be fine - this only shows up once all your shows have moved.