Redirect from youneedawiki link to custom domain#323

If a user has shared links to their youneedawiki.com wiki and later adds a custom domain, allow them to redirect the old wiki links to the new domain.

Job to be done:
When I’ve shared links to my wiki and later add a custom domain
I want redirect old links to my new custom domain
So all my users go to the same address

Potential implementation:

• Add a field to settings called URL redirect that is only seen for pro users under the youneedawiki.com address