feat: add user in db

src/databases/postgres/user_repository.rs

@@ -0,0 +1,17 @@
+use sqlx::PgPool;
+use uuid::Uuid;
+
+pub async fn ensure_user_exists(pool: &PgPool, user_id: Uuid) -> Result<(), sqlx::Error> {
+    sqlx::query!(
+        r#"
+        INSERT INTO auth.user (id)
+        VALUES ($1)
+        ON CONFLICT (id) DO NOTHING
+        "#,
+        user_id
+    )
+    .execute(pool)
+    .await?;
+
+    Ok(())
+}