title: Git pull from other user than in config
body: <p>I have repository created and the following <code>config</code> file:</p>
  
  <pre><code>[core]
      repositoryformatversion = 0
      filemode = true
      bare = false
      logallrefupdates = true
  [remote "origin"]
      url = https://user@github.com/repo/repo.git
      fetch = +refs/heads/*:refs/remotes/origin/*
  [branch "develop"]
      remote = origin
      merge = refs/heads/develop
  </code></pre>
  
  <p>Now when I use <code>git pull</code> I get notification to input password for <code>user</code> but I don't know this user password. However I know password for different user and this user has access to this repository. Is it possible to run <code>git pull</code> to enter different user than in <code>config</code> file not modifying this config file?</p>