Would I Need a Parent's Signature, or Can I Even Make This?

Okay. I'm making my own website and, to keep everyone contributing to the site(artists, coders, etc.) safe, I would like to make a contract between my individual staff members and myself. I'm only 16, so would I need a parent to sign it with me, or could I not do it, period? I would like this contract for the purpose of keeping any designs from being stolen and to keep people from being screwed out of something. Also, do you have any tips of what should be included in this contract?