make gesis prime

[minrk]

not to be merged without approval of @arnim and/or @rgaiacs

this should bring the top-level mybinder.org back up (#3160)

[rgaiacs]

Hi @minrk,

please correct me if I misunderstood something.

1. The user will visit https://mybinder.org/
2. https://mybinder.org/ will permanent redirect the user to https://notebooks,gesis.org

[manics]

It's a proxy not a redirect, so the existing GESIS BinderHub will appear as if it were hosted at mybinder.org in addition to its current host.

[rgaiacs]

Thanks @manics for the answer.

I will merge this and work to deploy a default brand BinderHub on the same server.