update schema

internal/db/schema.sql

@@ -1,7 +1,17 @@
+CREATE TABLE IF NOT EXISTS users (
+    id SERIAL PRIMARY KEY,
+    username TEXT NOT NULL UNIQUE,
+    email TEXT NOT NULL UNIQUE,
+    api_key TEXT UNIQUE,
+    storage_limit_bytes BIGINT DEFAULT 1073741824,
+    created_at TIMESTAMPTZ DEFAULT NOW()
+);
+
 CREATE TABLE IF NOT EXISTS buckets (
     id SERIAL PRIMARY KEY,
     name TEXT NOT NULL UNIQUE,
-    owner_id INT NOT NULL,
+    owner_id INT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    storage_used_bytes BIGINT DEFAULT 0,
     created_at TIMESTAMPTZ DEFAULT NOW()
 );