Refactor environment variables to use process.env in firebase configuration and update .gitignore for environment files

docker-compose.yml

@@ -1,12 +1,20 @@
 services:
   app:
     build: .
+    environment:
+      apiKey: ${apiKey}
+      authDomain: ${authDomain}
+      projectId: ${projectId}
+      storageBucket: ${storageBucket}
+      messagingSenderId: ${messagingSenderId}
+      appId: ${appId}
+      measurementId: ${measurementId}
     ports:
       - "80"
     deploy:
-      replicas: 3
+      replicas: 1
       restart_policy:
         condition: on-failure
       rollback_config:
         parallelism: 1
-        delay: 5s
+        delay: 5s