Added waitgroups practice exercise

Yes, I am back

waitgroups/go.mod

@@ -0,0 +1,3 @@
+module waitgroups
+
+go 1.23.1

waitgroups/main.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"sync"
+	"time"
+)
+
+var numberList = []int{1, 2, 3, 4, 5}
+
+func main() {
+	var a sync.WaitGroup
+
+	for _, v := range numberList {
+		a.Add(1)
+		go func() {
+			defer a.Done()
+			worker(v)
+		}()
+	}
+	a.Wait()
+}
+
+func worker(id int) {
+	fmt.Printf("Worker %v is starting\n", id)
+	time.Sleep(time.Duration(rand.Intn(10) * int(time.Second)))
+	fmt.Printf("Worker %v is done\n", id)
+}