Install ember-scroll

Author: jaredgalanis

Diff for: package.json

@@ -96,6 +96,7 @@
     "ember-resolver": "^8.0.3",
     "ember-rfc176-data": "^0.3.17",
     "ember-route-action-helper": "^2.0.8",
+    "ember-scroll": "^1.0.3",
     "ember-showdown-shiki": "^1.2.1",
     "ember-sinon": "^4.1.1",
     "ember-source": "~3.28.8",