gitpod: Make Gitpod's automated dev setup automatically run Jekyll and Parcel (#1586)

.gitpod.yml

@@ -1,10 +1,15 @@
 image: gitpod/workspace-full
 
+ports:
+  - port: 4001
+    onOpen: open-preview
+
+tasks:
+  - init: yarn install && bundle install
+    command: env PORT=4001 yarn run dev
+
 github:
-  # Prebuild the docker image for gitpod - https://www.gitpod.io/docs/46_prebuilds/
+  # Prebuild the docker image for gitpod - https://www.gitpod.io/docs/prebuilds/
   prebuilds:
     # enable for the master/default branch
     master: true
-
-tasks:
-  - init: bundle install