gddo-server: add UI to turn on/off redirect to

This change adds UI for the option to set a cookie and have
candidate links redirect to their equivalent
counterparts. If a user returns to with the utm_source
form value equal to 'backtogodoc', it will display an option to
turn off the automatic redirect.

The intention is to have a link on that allows the
user to return to and also turn off the automatic redirect
without having to know the special URL param values.

Updates golang/go#37099

Change-Id: I27bd03cbc484a1e504795ff669224c2a2a7d72b6
Reviewed-by: Jonathan Amsterdam <>
Reviewed-by: Alexander Rakoczy <>
5 files changed