title: git does not ignore a file
body: <p>I accidentally tracked the <code>.idea/workspace.xml</code> file created by rubymine and now i can't seem to remove the file from being tracked. </p>
  
  <p>It's been checked in multiple times because of this, but i'd really like it to stop being tracked because is causes merge conflicts. </p>
  
  <p>Here's how i keep trying to remove the file. </p>
  
  <ol>
  <li><p><code>git rm --cached .idea/workspace.xml</code></p>
  
  <pre><code>$ git status
  On branch master
  Changes to be committed:
  (use "git reset HEAD &lt;file&gt;..." to unstage)
  
  deleted:    .idea/workspace.xml
  </code></pre></li>
  <li><p><code>git commit -m 'remove workspace file from tracking'</code></p></li>
  <li>add this entry to my .gitignore file <code>.idea/*</code></li>
  </ol>