title: could not translate host name "postgres" to address: Unknown host
body: <p>Setting up a Django project but I am getting a warning about setting up <code>postgres</code> as shown in the title, but I am unsure what this means.</p>
  <p><strong>Full warning message:</strong></p>
  <pre><code>RuntimeWarning: Got an error checking a consistent migration history performed for database connection 'default': could not translate host name &quot;postgres&quot; to address: Unknown host
  </code></pre>
  <p><strong>And here is how I define <code>postgres</code> in my <code>settings.py</code>:</strong></p>
  <pre><code>DATABASES = {
  &quot;default&quot;: {
      &quot;ENGINE&quot;: &quot;django.db.backends.postgresql_psycopg2&quot;,
      &quot;NAME&quot;: os.environ.get(&quot;DB_NAME&quot;, &quot;dbname&quot;),
      &quot;USER&quot;: os.environ.get(&quot;DB_USER&quot;, &quot;dbuser&quot;),
      &quot;PASSWORD&quot;: os.environ.get(&quot;DB_PASSWORD&quot;, &quot;dbpassword&quot;),
      &quot;HOST&quot;: os.environ.get(&quot;DB_HOST&quot;, &quot;postgres&quot;),
      &quot;PORT&quot;: os.environ.get(&quot;DB_PORT&quot;, &quot;5432&quot;),
  }
  </code></pre>
  <p>}</p>
  <p>Would it possible for someone to walk me through what is going wrong here? I have no idea.</p>