Doc - update documentation build

docs/installation.html

@@ -960,6 +960,7 @@ server {
 </ul>
 <div class="highlight-bash notranslate"><div class="highlight"><pre><span></span>$ git clone https://github.com/SamR1/FitTrackee.git
 $ <span class="nb">cd</span> FitTrackee
+$ cp .env.docker .env
 $ make docker-build docker-run docker-init
 </pre></div>
 </div>