fix: change optional field teacherId to default

Author: adgator101

prisma/schema.prisma

@@ -16,6 +16,7 @@ model User {
   faculty faculty
   batch   String
   group   String
+  role    role
 }
 
 model Routine {
@@ -57,11 +58,17 @@ model Subject {
   subjectCode String
   timeTables  TimeTable[]
   Teacher     Teacher     @relation(fields: [teacherId], references: [id])
-  teacherId   Int?
+  teacherId   Int
 }
 
 enum faculty {
   BCS
   BIBM
   BIHMS
 }
+
+enum role{
+  admin
+  teacher
+  student
+}