Ability to add Mentors to Batches

[binnyva]

Summary

We should be able to assign mentors to batches. Multiple mentors per batch if need be.

Page/Module

Shelter > Batches > Edit Batch - Eg. https://makeadiff.in/madnet/#/shelters/244/projects/4/batches/3846

API

POST /batches/{batch_id}/mentors - Documentation

[craterkamath]

I will be working on this issue! Thanks :D

[craterkamath]

Opened #116 for the enhancement. @binnyva Can you please take a look at this and review?

[craterkamath]

I have not added a dedicated section "Mentor Assignments" per say (just like "Teacher Assignments") in the /shelters/XXX. But it can be easily added since /shelters/XXX/batches/0/ directs to the over page: currently the "Add Mentors" button is disabled on that page. But this would need us to add an additional page(just like in the "Teacher Assignments" case) or we can add a button per item in the overview list (just like in the "Class Sections") case. Happy to discuss further on this since the changes can come in a different patchset.

[binnyva]

Works perfectly! Thanks :-D