time based on periods rather than timestamps

backend/createtable.sql

@@ -16,8 +16,8 @@ CREATE TABLE Rooms (
 
 CREATE TABLE TimeSlots (
     Id INTEGER PRIMARY KEY ASC AUTOINCREMENT,
-    TimeStart TEXT,
-    TimeEnd TEXT,
+    Period INTEGER,
+    Day INTEGER,
     Room INTEGER,
     FOREIGN KEY(Room) REFERENCES Rooms(Id)
 );