In this folder are the migrations used to generate the database tables and initialize them. They are plain SQL files in the respective dialect that each database supports. More information about migrations can be found on Diesel's website

Migrations are organized according to which database they are for since each database software has its own syntax ie SERIAL in Postgres vs AUTOINCREMENT in SQLite. Each database folder contains a series of folders dated and named based on the migration with an up.sql and a down.sql file to apply and revert the migration.