chore(demo): added hammerjs

Author: AnthonyNahas

demo/package.json

@@ -47,6 +47,7 @@
     "bootstrap": "^4.1.3",
     "core-js": "^2.6.0",
     "font-awesome": "^4.7.0",
+    "hammerjs": "^2.0.8",
     "highlight.js": "^9.13.1",
     "include-media": "^1.4.9",
     "material-design-icons": "^3.0.1",