diff --git a/src/playground/README.md b/src/playground/README.md
new file mode 100644
index 00000000..93a82df2
--- /dev/null
+++ b/src/playground/README.md
@@ -0,0 +1,5 @@
+# Playground
+
+You may use `playground.js` file to play with data
+structures and algorithms. The code from `playground.js` may
+be tested in `./__test__/playground.test.js` file.