title: Can't run example code referenced in Flask docs
body: <p>I am reading the Flask docs and want to use the examples they reference that are in the git repo.  However, the tutorials don't match the code in the repository, and I can't run them; I get the following error:</p>
  
  <pre><code>  @app.cli.command('initdb')
  AttributeError: 'Flask' object has no attribute 'cli'
  </code></pre>
  
  <p>I used <code>pip install flask</code> to install Flask.  Why can't I run the repo code?</p>