Swig is a mobile app that allows users to explore new drinks, share them with others, earn rewards, and gameify their experiences. The app's team consists of two people, the sole engineer and his partner, who initially used Ruby on Rails and Postgres for hosting, but later switched to MongoDB due to its flexibility and schemaless design, which allowed for faster development and integration with Rails. However, as the user base grew, performance issues arose, and the team had to denormalize their data and use Redis for caching, leading to increased complexity and maintenance costs. To mitigate these issues, the team switched to Neo4j, a schemaless graph database that provided flexibility, ease of querying complex relationships, and a simpler persistence layer, resulting in a reduced codebase and improved performance.