There have been major changes in the plan in my project since the last update. We have decided to host the explorations on Google AppEngine for now. And we’ll have a OpenHatch api for mission specific stuff that can’t be done on GAE. Our Oppia will talk to that api to perform those special parts.
I have implemented a minimal version of the tar mission on AppEngine. Oppia didn’t have a widget for file upload, so I made one. But it’s more of a fire reading widget because technically we are uploading the file but not storing it in the datastore. The current version of mission can be seen here.