init: scaffold from k-template with postgres + worker

crates/adapters/postgres/src/db.rs

@@ -0,0 +1,14 @@
+pub type PgPool = sqlx::PgPool;
+
+pub async fn connect(url: &str) -> anyhow::Result<PgPool> {
+    let pool = sqlx::postgres::PgPoolOptions::new()
+        .max_connections(10)
+        .connect(url)
+        .await?;
+    Ok(pool)
+}
+
+pub async fn run_migrations(pool: &PgPool) -> anyhow::Result<()> {
+    sqlx::migrate!("./migrations").run(pool).await?;
+    Ok(())
+}