title: Two users trying to push two branches with the same name
body: <p>Here's my scenario: there are two users, they both cloned the same repository (so this means they have the same remote).
  One creates a branch locally, let's say 'branch1' starts some developing/committing in it, and in the end wish to push the branch to remote.
  This is possible.</p>
  
  <p>However, the second one does the same, creates a branch with the same name ('branch1'), commits something in it and in the end wish to push;
  Is this possible? Which commands should he run in order to work? Is it enough a pull before doing the push?</p>
  
  <p>Thanks.</p>