adding demo gif (#229)

diff --git a/knative-build/media/demo-nodejs-helloworld.gif b/knative-build/media/demo-nodejs-helloworld.gif
new file mode 100644
index 0000000..c84aee5
--- /dev/null
+++ b/knative-build/media/demo-nodejs-helloworld.gif
Binary files differ
diff --git a/knative-build/runtimes/javascript/README.md b/knative-build/runtimes/javascript/README.md
index 1a06374..413f571 100644
--- a/knative-build/runtimes/javascript/README.md
+++ b/knative-build/runtimes/javascript/README.md
@@ -311,4 +311,4 @@
 
 ### See Hello World Live in Action
 
-* [Screen Recording of Hello World](https://youtu.be/BG1t2t7UvUA)
+![Screen Recording of Hello World](../../media/demo-nodejs-helloworld.gif)