support postgresql as database option

server/db/README.md

@@ -0,0 +1,66 @@
+# Database
+
+Pangolin can use a Postgres or SQLite database to store its data.
+
+## Development
+
+### Postgres
+
+To use Postgres, edit `server/db/index.ts` to export all from `server/db/pg/index.ts`:
+
+```typescript
+export * from "./pg";
+```
+
+Make sure you have a valid config file with a connection string:
+
+```yaml
+postgres:
+    connection_string: postgresql://postgres:postgres@localhost:5432
+```
+
+You can run an ephemeral Postgres database for local development using Docker:
+
+```bash
+docker run -d \
+  --name postgres \
+  --rm \
+  -p 5432:5432 \
+  -e POSTGRES_PASSWORD=postgres \
+  -v $(mktemp -d):/var/lib/postgresql/data \
+  postgres:17
+```
+
+### SQLite
+
+To use SQLite, edit `server/db/index.ts` to export all from `server/db/sqlite/index.ts`:
+
+```typescript
+export * from "./sqlite";
+```
+
+No edits to the config are needed. If you keep the Postgres config, it will be ignored.
+
+## Generate and Push Migrations
+
+Ensure drizzle-kit is installed.
+
+### Postgres
+
+You must have a connection string in your config file, as shown above.
+
+```bash
+npm run db:pg:generate
+npm run db:pg:push
+```
+
+### SQLite
+
+```bash
+npm run db:sqlite:generate
+npm run db:sqlite:push
+```
+
+## Build Time
+
+There is a dockerfile for each database type. The dockerfile swaps out the `server/db/index.ts` file to use the correct database type.