title: git github cannot push to origin
body: <p>I may be missing something, but I'm sure that I've checked everything,
  I forked a repo and cloned it on my system,
  made some changes
  after commiting 
  did <code>git push origin master</code></p>
  
  <p>it says </p>
  
  <pre><code>fatal: remote error: 
    You can't push to git://github.com/my_username/my_repo.git
    Use git@github.com:my_username/my_repo.git
  </code></pre>
  
  <p>Am I missing something?
  then I tried 
  <code>
  git remote add origin https://github.com/my_username/my_repo.git
  </code></p>
  
  <p>it returned </p>
  
  <p>fatal: remote origin already exists.</p>
  
  <p>I dont understand why this is hapenning, pls help</p>