
ArangoDB
I would love to introduce you to the open source NoSQL database ArangoDB :) I'm part of the Core Team and among other things work on the Ruby driver and the ORM for Ruby (with a focus on Rails): I'd like to show those gems as well :)
ArangoDB is an open source NoSQL database which is not narrow-mindedly focused on horizontal scalability. Instead, ArangoDB aims to offer developers great flexibility and ease-of-use. The database is suitable for use cases which are difficult to implement with most traditional relational databases and also many of the other NoSQL databases.