Username problems

[ludomelodia]

I must have made an error when I first downloaded git-it because it seems to think that my first name is my username. So it won't let me pass certain challenges even though I completed them since it doesn't find them completed for a user with a name that isn't my username. Is there a way I can fix this? I've looked everywhere in the app but I can't seem to find anywhere that will allow me to change my username.