Update database.py

database.py

@@ -31,10 +31,10 @@ def init_db(app):
             CREATE TABLE IF NOT EXISTS users (
                 id INTEGER PRIMARY KEY AUTOINCREMENT,
                 udid TEXT NOT NULL UNIQUE,
-                name TEXT DEFAULT NULL,
+                name TEXT DEFAULT '',
                 premium_account BOOLEAN DEFAULT FALSE,
                 usage_limit INTEGER DEFAULT 10,
-                invoice TEXT DEFAULT NULL
+                invoice TEXT DEFAULT ''
             )
         ''')
         
@@ -42,6 +42,6 @@ def init_db(app):
         if cursor.fetchone()[0] == 0:
             cursor.executemany('INSERT INTO users (udid, name, premium_account, usage_limit, invoice) VALUES (?, ?, ?, ?, ?)',
                              [('test_udid_1', 'Test User 1', True, 4, 'test_invoice_1'), 
-                              ('test_udid_2', 'Test User 2', False, 4, None)])
+                              ('test_udid_2', 'Test User 2', False, 4, 'test_invoice_2')])
         
         db.commit()