When installing redmine through 'apt-get install redmine', you get suggested either of the SQLlite or MySQL DBMS within the installed UI. If you choose MySQL, you hit this issue indeed.
But if you install with 'apt-get install redmine redmine-mysql', you do not hit the issue.
Indeed, 'ruby-mysql' is a child/dependency of 'redmine-mysql'.
When installing redmine through 'apt-get install redmine', you get suggested either of the SQLlite or MySQL DBMS within the installed UI. If you choose MySQL, you hit this issue indeed.
But if you install with 'apt-get install redmine redmine-mysql', you do not hit the issue.
Indeed, 'ruby-mysql' is a child/dependency of 'redmine-mysql'.