title: "bundle exec rake db:test:prepare" vs "bundle exec rake db:populate"
body: <p>I'm going through Michael Hartl's tutorial and I'm unsure what the difference between these 2 commands is. Generally, in the tutorial, there's always 3 steps.</p>
  
  <pre><code>1. bundle exec rake db:reset
  </code></pre>
  
  <p>This makes sense, to reset the databse. </p>
  
  <pre><code>2. bundle exec rake db:populate
  </code></pre>
  
  <p>I figure this is to populate the database with the sample data.</p>
  
  <pre><code>3. bundle exec rake db:test:prepare
  </code></pre>
  
  <p>Why is this command still needed?</p>