Add SQLite support

[HendricksJudy]

Related to #49

Add support for SQLite as an alternative to PostgreSQL.

• docker-compose.yaml

  • Add a new service for SQLite.
  • Update the app service to use SQLite if specified.
  • Add a volume for SQLite data.

• prisma/schema.prisma

  • Update the datasource db block to support both PostgreSQL and SQLite.

• src/lib/prisma.ts

  • Update the createPrismaClient function to support both PostgreSQL and SQLite.

• .env.example

  • Add an example DATABASE_URL for SQLite.