Don't insert duplicate schedule

database.py

@@ -36,6 +36,19 @@ def get_schedules_for_user(user_id):
     ) for row in rows]
 
 def insert_schedule(schedule):
+    cur = connection.execute('''
+    SELECT created_at
+    FROM schedule
+    WHERE time = ? and day_week = ? and location = ? and meal = ? and user_id = ?
+    ''', (
+        schedule.time,
+        schedule.day_week,
+        schedule.location.name,
+        schedule.meal.name,
+        schedule.user_id
+    ))
+    row = cur.fetchone()
+    if not row:
         connection.execute('''
         INSERT INTO schedule
         (time, day_week, location, meal, user_id, created_at)