Simple app for fire dept.

I am a FF that is looking to create an app for us to be able to do shift trades. Nothing complex just needs the ability for users to upload dates from their phones when they need covered for trades. I am not versed in apps so I am not sure if this is a easy project or not. I am paying for this personally so if it is outrageous I guess then that's why it hasn't been done. Simple and easy to use. If affective I would like this to be able to be rolled out to different departments. Not trying to make money off this just trying to simplify the ability to communicate.