Actually the regular one is already there, I just need the releases one added, which I typoed..... should be:
http://fedorahosted.org/released/imapsync to
https://releases.pagure.org/imapsync/

These redirects are now in ansible (and setup on proxies).

I've added the released one:

RewriteRule ^/imapsync https://pagure.io/imapsync [R=301]
RewriteRule ^/releases/i/m/imapsync/(.) https://pagure.io/releases/imapsync/$1 [R=301]
RewriteRule ^/releases/i/m/imapsync https://pagure.io/releases/imapsync [R=301]
RewriteRule ^/released/i/m/imapsync/(.) https://pagure.io/releases/imapsync/$1 [R=301]
RewriteRule ^/released/i/m/imapsync https://pagure.io/releases/imapsync [R=301]
RewriteRule ^/released/imapsync https://pagure.io/releases/imapsync [R=301]

Should be live in a while after the proxy playbook finishes.