diff --git a/server/Dockerfile b/server/Dockerfile
index c8487a2..ac84eb4 100644
--- a/server/Dockerfile
+++ b/server/Dockerfile
@@ -4,6 +4,9 @@ WORKDIR /app
 
 COPY . .
 
+RUN npm config set registry https://registry.npmmirror.com/
+RUN npm install
+
 EXPOSE 3000
 
-CMD ["npm", "start"]
+CMD ["node", "server.js"]
diff --git a/server/public/index.html b/server/public/index.html
index 9d5e538..103d35d 100644
--- a/server/public/index.html
+++ b/server/public/index.html
@@ -12,7 +12,8 @@
 
 <div id="messageContainer"></div>
 <script>
-  const ws = new WebSocket('ws://localhost:3000');
+  const port = !window.location.port ? '' : `:${window.location.port}`;
+  const ws = new WebSocket(`ws://${window.location.hostname}${port}`);
   const messageContainer = document.getElementById('messageContainer');
 
   ws.onmessage = function(event) {