Improve documentation about increasing number of maximum connections
There is at least one report related to increase of maximum connections for two-connection setup. We need to improve visibility of https://docs.gitlab.com/omnibus/settings/database.html#configuring-multiple-database-connections
Possible options:
- We advise to run
rake gitlab:check
. Maybe integrate the maximum-connection check in that rake task - Mention connection checking on https://docs.gitlab.com/ee/administration/postgresql/multiple_databases.html