Thêm tính năng bình luận ở mỗi điểm của chặng

backend/prisma/schema.prisma

@@ -73,6 +73,8 @@ model User {
   receivedJoinRequests    JoinRequest[]      @relation("JoinRequester")
   uploadedPhotos          Photo[]
   paidExpenses            Expense[]          @relation("ExpensePaidBy")
+  comments                Comment[]
+
 }
 
 model Tour {
@@ -157,6 +159,7 @@ model Location {
   leg             Leg       @relation(fields: [legId], references: [id], onDelete: Cascade)
   expenses        Expense[]
   photos          Photo[]
+  comments        Comment[]
 }
 
 model Expense {
@@ -188,3 +191,13 @@ model Photo {
   location     Location?    @relation(fields: [locationId], references: [id], onDelete: SetNull)
   uploader     User         @relation(fields: [uploaderId], references: [id])
 }
+
+model Comment {
+  id         String   @id @default(uuid())
+  content    String
+  createdAt  DateTime @default(now())
+  locationId String
+  location   Location @relation(fields: [locationId], references: [id], onDelete: Cascade)
+  userId     String
+  user       User     @relation(fields: [userId], references: [id], onDelete: Cascade)
+}