This returns the ActiveRecord configuration for the current environment.
While CE doesn't use this very often, EE will use it in a few places for
the database load balancing code. I'm adding this to CE so we don't end
up with merge conflicts in this file.
This allows you to set a custom host when calling
Gitlab::Database.create_connection_pool. This is necessary for load
balancing as in this case we want to inherit all settings except for the
hostname.
We don't need to connect when requesting the name of the database
adapter. This in turn should prevent us from requesting/leaking
connections just by asking whether we're using PostgreSQL or MySQL.
