title: Git: permission to [organization] denied to [user]
body: <p>I have two accounts on Github (let's say they are <code>a1</code> and <code>a2</code>). With my <code>a2</code> profile, I created an origanization and a new repository for it (from Github's website). My computer has the following <code>~/.gitconfig</code> file:</p>
  
  <pre><code>[core]
      editor = pico
  [user]
      name = a1
      email = mail_a1@example.com
  </code></pre>
  
  <p>(because most of the time I use my <code>a1</code> account).</p>
  
  <p>Now I wanted to work on the repository of the organisation I created with <code>a2</code> so I did the following:</p>
  
  <pre><code>cd project_folder
  touch README.md
  git init
  git config --local user.name a2
  git config --local user.email "mail_a2@example.com"
  git add README.md
  git commit -m "first commit"
  git remote add origin https://github.com/myorganisation/myrepo.git
  </code></pre>
  
  <p>Then, just to be sure my commit was done by <code>a2</code>, I did <code>git log</code>, obtaining:</p>
  
  <pre><code>commit e8dd182a12023a490cb2f099ea8b3a94afe6b81b
  Author: a2 &lt;mail_a2@example.com&gt;
  Date:   Wed Dec 14 17:12:10 2016 +0100
  
      first commit
  </code></pre>
  
  <p>Great. But when I tried to <code>git push -u origin master</code>, I got a 403 message saying that I was trying to push as <code>a1</code>:</p>
  
  <pre><code>remote: Permission to hivex-unipd/swedesigner.git denied to gigiobello.
  fatal: unable to access 'https://github.com/myorganisation/myrepo.git/': The requested URL returned error: 403
  </code></pre>
  
  <p>Did I forget something? <strong>Why does Github thinks I'm <code>a1</code></strong> even after I'v configured my local repository with the <code>a2</code> account?</p>