Update README.md (#41)

JB1905 · web-flow · commit 0f337319da6a · 2021-10-09T23:54:57.000+02:00
diff --git a/README.md b/README.md
@@ -11,6 +11,10 @@
 
 Currency converter React hook
 
+### Demo
+
+**[Playground – play with library in CodeSandbox](https://codesandbox.io/s/react-currency-hooks-l3b1l)**
+
 ### Similar Projects
 
 - [Cashify](https://github.com/xxczaki/cashify/) by [Antoni Kepinski](https://github.com/xxczaki/)
