REFINE OAuth2 user handling and update database schema

src/main/resources/db/schema.sql

@@ -2,18 +2,17 @@ DROP TABLE IF EXISTS clips;
 DROP TABLE IF EXISTS users;
 
 CREATE TABLE IF NOT EXISTS users (
-    id BIGINT PRIMARY KEY,
+    id BIGSERIAL PRIMARY KEY,
     google_id VARCHAR(64),
     username VARCHAR(50) NOT NULL UNIQUE,
     email VARCHAR(100) NOT NULL UNIQUE,
     name VARCHAR(100) NOT NULL,
     role INTEGER DEFAULT 0,
     created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
-);
-
+    );
 
 CREATE TABLE IF NOT EXISTS clips (
-    id BIGINT PRIMARY KEY,
+    id BIGSERIAL PRIMARY KEY,
     user_id BIGINT NOT NULL,
     title VARCHAR(255) NOT NULL,
     description TEXT,