I wanted to explore Mongo to understand what situations one might want to opt for a document based NoSQL database, and have used Mongo several times for simple backends for pet projects when I was initially getting comfortable with React. I am familiar with using an ORM (mongoose), and how to express relationships in a non-relational database. At one point when experimenting with Elasticsearch (github), I had to figure out a way to autoindex from Mongo and ended up doing so by creating a replica shard that was tailed by Composer (an open source project from IBM), and it taught me alot about how Mongo replication and sharding works.