title: How to delete all unpushed commits without deleting local changes
body: <p>I'm working with a friend on a personal project but we are both kinda new to git.</p>
  <p>We already had our project (a game server) and my friend installed github desktop on the server.</p>
  <p>He added all the files from our game server, made a commit and some modifications that he also commited.</p>
  <p>The thing is that the whole folder is almost 3go and most of it (~2go) are big modelisation files that we don't really wanted to commit.</p>
  <p>Nothing have been pushed on git yet because github wont let us (from what i've seen it's because of the size of our project) so all the commits are in local.</p>
  <p>How can we delete all the commits without losing our changes, so we can ignore the big files, add only those we want to track and finally push?
  Or is there a best way to do so?</p>
  <p>Thanks.</p>