Added check for REDIS_URL. Closes #3677.

scripts/check-db.js

@@ -36,6 +36,10 @@ async function checkEnv() {
   } else {
     success('DATABASE_URL is defined.');
   }
+
+  if (process.env.REDIS_URL) {
+    success('REDIS_URL is defined.');
+  }
 }
 
 async function checkConnection() {