Add build step and specify command for running SSR in Dockerfile

client/Dockerfile

@@ -13,8 +13,11 @@ RUN npm install
 # Copy the rest of the client code to the container
 COPY . .
 
+# Build
+RUN npm run build
+
 # Expose the port the client runs on
 EXPOSE 3000
 
 # Command to run the client
-CMD ["npm", "start"]
+CMD ["npm", "run", "ssr"]