feat: add basic Docker configuration for backend and frontend services

backend/docker/entrypoint.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+function exit_container_SIGTERM(){
+  echo "Caught SIGTERM"
+  exit 0
+}
+trap exit_container_SIGTERM SIGTERM
+
+echo "Setting /app/public ownership..."
+chgrp -R 33 /app
+chown -hR 33:33 /app
+
+echo "Starting PHP-FPM..."
+php-fpm -F & wait