feat: add Redis client singleton

apps/web/src/lib/redis.ts

@@ -0,0 +1,12 @@
+import IORedis from "ioredis";
+
+let redis: IORedis | null = null;
+
+export function getRedis(): IORedis {
+  if (!redis) {
+    redis = new IORedis(process.env.REDIS_URL ?? "redis://localhost:6379", {
+      maxRetriesPerRequest: null,
+    });
+  }
+  return redis;
+}