Specify how to update the db timeouts

doc/administration/troubleshooting/postgresql.md

@@ -157,7 +157,7 @@ See current settings with:
 
 ```shell
 sudo gitlab-rails runner "c = ApplicationRecord.connection ; puts c.execute('SHOW statement_timeout').to_a ;
-puts c.execute('SHOW lock_timeout').to_a ;
+puts c.execute('SHOW deadlock_timeout').to_a ;
 puts c.execute('SHOW idle_in_transaction_session_timeout').to_a ;"
 ```
 
@@ -165,9 +165,19 @@ It may take a little while to respond.
 
 ```ruby
 {"statement_timeout"=>"1min"}
-{"lock_timeout"=>"0"}
+{"deadlock_timeout"=>"0"}
 {"idle_in_transaction_session_timeout"=>"1min"}
 ```
 
+These settings can be updated in `/etc/gitlab/gitlab.rb` with:
+
+```ruby
+postgresql['deadlock_timeout'] = '5s'
+postgresql['statement_timeout'] = '15s'
+postgresql['idle_in_transaction_session_timeout'] = '60s'
+```
+
+Once saved, [reconfigure GitLab](../restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
+
 NOTE:
 These are Omnibus GitLab settings. If an external database, such as a customer's PostgreSQL installation or Amazon RDS is being used, these values don't get set, and would have to be set externally.