Training path

I work with a non profit organization that has created its own Web based volunteer signup system which utilizes SQl, Ruby, Javascript HTML and Css. The system is in need of an overhaul and the individual that created it isn’t very involved anymore. We are considering rebuilding the system. I have familiarity with all of the above (not so much Ruby) and I am part of the team that will re-build the system.

I am trying to have a DB of volunteer shifts which users can use a web interface to sign up for. I want them to be able to login to the system at anytime so they can see the history of the shifts they have signed up for and do any necessary updates. Administrators need to login and mange the users and the shifts.

I am looking to see if there is a path that hits those class concepts needed to create this. We want to keep this at a low tech level as we don’t have high level programmers available to maintain the system.

Please let me know your thoughts on what I should focus on and use.