update db schema

src/schemas/database.py

@@ -16,10 +16,10 @@ LOANS = """CREATE TABLE IF NOT EXISTS loans (
 id INTEGER PRIMARY KEY AUTOINCREMENT,
 user_id INTEGER NOT NULL,
 media_id INTEGER NOT NULL,
-loan_date DATETIME NOT NULL,
-return_date DATETIME NOT NULL,
+loan_date TEXT NOT NULL,
+return_date TEXT NOT NULL,
 returned INTEGER DEFAULT 0,
-returned_date DATETIME,
+returned_date TEXT,
 FOREIGN KEY (user_id) REFERENCES users(id),
 FOREIGN KEY (media_id) REFERENCES media(id));
 """