title: Cannot push to Heroku because key fingerprint
body: <p>I am new to Rails, and I was trying to deploy a very simple app to Heroku. This is the second app that I deploy, and the first one I was able to do it just fine. However I am having some issues with this one. Whenever I "<strong>git push heroku master</strong>", I get this error:</p>
  
  <blockquote>
    <p>!  Your key with fingerprint xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx is not authorized to >access my_heroku_app.</p>
    
    <p>fatal: The remote end hung up unexpectedly</p>
  </blockquote>
  
  <p>I have tried to manage my keys after logging in heroku. If I type in my console "<strong>heroku keys</strong>", then I get:</p>
  
  <blockquote>
    <p>No keys for myemailaddress.</p>
  </blockquote>
  
  <p>However, If I run the comand "<strong>heroku keys:add</strong>" I get</p>
  
  <blockquote>
    <p>Found existing public key: /Users/michele/.ssh/id_rsa.pub
    Uploading ssh public key /Users/michele/.ssh/id_rsa.pub
    !    Fingerprint already exists. Please use one ssh key per Heroku account</p>
  </blockquote>
  
  <p>Please help me! This is soo frustating, I have no idea what's wrong!
  Thank you</p>