Add example in README

README.md

@@ -20,10 +20,62 @@ Priority pool:
 
 ## Install
 
-```powershell
+```
 go get -u github.com/alexvanin/priopool
 ```
 
+## Example
+
+```go
+package main
+
+import (
+	"fmt"
+	"log"
+	"sync"
+	"time"
+
+	"github.com/alexvanin/priopool"
+)
+
+func main() {
+	regularJob := func(i int) {
+		time.Sleep(1 * time.Second)
+		fmt.Printf("Job %d is done\n", i)
+	}
+
+	highPriorityJob := func() {
+		fmt.Println("High priority job is done")
+	}
+
+	pool, err := priopool.New(2, -1) // pool for two parallel executions
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	wg := new(sync.WaitGroup)
+	wg.Add(5 + 1)
+	for i := 0; i < 5; i++ {
+		ind := i + 1
+		// enqueue 5 regular jobs
+		pool.Submit(1, func() { regularJob(ind); wg.Done() })
+	}
+	// after 5 regular jobs enqueue high priority job
+	pool.Submit(10, func() { highPriorityJob(); wg.Done() })
+	wg.Wait()
+
+	/*
+		Output:
+		Job 2 is done
+		Job 1 is done
+		High priority job is done
+		Job 4 is done
+		Job 3 is done
+		Job 5 is done
+	*/
+}
+```
+
 ## License
 
 Source code is available under the [MIT License](/LICENSE).