Include a note for people that think the headers are wrong.

doc/update/6.0-to-6.5.md

@@ -53,10 +53,10 @@ sudo -u git -H git checkout v1.8.0 # Addresses multiple critical security vulner
 ```bash
 cd /home/git/gitlab
-# MySQL
+# MySQL installations (note: the line below states '--without ... postgres')
 sudo -u git -H bundle install --without development test postgres --deployment
-#PostgreSQL
+# PostgreSQL installations (note: the line below states '--without ... mysql')
 sudo -u git -H bundle install --without development test mysql --deployment

doc/update/6.4-to-6.5.md

@@ -33,10 +33,10 @@ sudo -u git -H git checkout v1.8.0
 ```bash
 cd /home/git/gitlab
-# MySQL
+# MySQL installations (note: the line below states '--without ... postgres')
 sudo -u git -H bundle install --without development test postgres --deployment
-# PostgreSQL
+# PostgreSQL installations (note: the line below states '--without ... mysql')
 sudo -u git -H bundle install --without development test mysql --deployment