add some definitions to readme

boilerplates-concurrency/thread_example.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+
+import time
+import random
+import threading
+
+
+def worker(n):
+    sleep = random.randrange(1, 10)
+    time.sleep(sleep)
+    print("Worker {} from {}: sleeping for {} seconds.".format(n, threading.get_ident(), sleep))
+
+
+for i in range(5):
+    t = threading.Thread(target=worker, args=(i,))
+    t.start()