Setup grading infrastructure for prep course

[buedaswag]

• Simple heroku app that receives requests from the students’s notebooks with the notebook grade
• we should probably create a repo for the app code

[buedaswag]

@rjna @InesPessoa how's progress on this? do you need any help?

[Juliana-R]

Shall we close this?

[Juliana-R]

I believe this was already done in another repo. Please reopen if necessary.