added example usage of set datastructure

Author: avinashkrishna613

examples/set.js

@@ -0,0 +1,20 @@
+// An example explaining how to add values to a set and how to retrive them
+
+import { createClient } from 'redis';
+
+const client = createClient();
+await client.connect();
+
+// if you try to add any data of type other than string you will get an error saying `Invalid argument type`
+// so before adding make sure the value is of type string or convert it using toString() method
+// https://redis.io/commands/sadd/
+await client.SADD("user1:favorites", "1");
+
+// retrieve values of the set defined
+// https://redis.io/commands/smembers/
+const favorites = await client.SMEMBERS("user1:favorites");
+for (const favorite of favorites) {
+    console.log(favorite);
+}
+
+await client.quit();