title: WARNING: toctree contains reference to nonexisting document
body: <p>I'm using sphinx for documenting my Django application.</p>
  
  <p>I have the following directory structure of docs</p>
  
  <pre><code>docs
  |- build
  |- source
     |- _static
     |- _templates
     |- conf.py
     |- index.rst
     |- upgrade.rst
  |- upgrade_changes
     |- migration
        |- index.rst
     |- index.rst
     |- library_changes.rst
  </code></pre>
  
  <p>and the content of <code>docs/source/index.rst</code> is</p>
  
  <pre><code>My App's documentation!
  =============================================
  App Description
  
  Revamp Upgrade Changes
  ----------------------
  
  .. toctree::
     :maxdepth: 2
  
     upgrade
  </code></pre>
  
  <p>the <code>source/upgrade.rst</code> file inludes the content from <code>upgrade_changes</code></p>
  
  <pre><code>.. include:: ../upgrade_changes/index.rst
  </code></pre>
  
  <p>And the <code>/upgrade_changes/index.rst</code> has</p>
  
  <pre><code>Following is the list of all revamp related documentation.
  
  .. toctree::
     :maxdepth: 2
  
     library_changes
  </code></pre>
  
  <p>I want to include a <strong>toctree</strong> for the <code>library_changes.rst</code> file which is at the same level os of <code>index.rst</code>.</p>
  
  <p>But this gives an error</p>
  
  <pre><code>upgrade_changes/index.rst:50: WARNING: toctree contains reference to nonexisting document 'library_changes'
  </code></pre>
  
  <p><strong>How can I include the files to toctree at the same level?</strong></p>