Add Child functionality

prisma/migrations/20250412114412_add_gender_to_child/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Child" ADD COLUMN     "gender" TEXT;

prisma/schema.prisma

@@ -22,15 +22,16 @@ model User {
 }
 
 model Child {
-  id        Int       @id @default(autoincrement())
-  name      String
-  birthDate DateTime
-  userId    String
-  user      User      @relation(fields: [userId], references: [id])
+  id          Int       @id @default(autoincrement())
+  name        String
+  birthDate   DateTime
+  gender      String?   // can be "male", "female", "diverse", or "unknown"
+  userId      String
+  user        User      @relation(fields: [userId], references: [id])
   measurements Measurement[]
-  teeth     ToothStatus[]
-  vaccines  Vaccine[]
-  createdAt DateTime  @default(now())
+  teeth       ToothStatus[]
+  vaccines    Vaccine[]
+  createdAt   DateTime  @default(now())
 }
 
 model Measurement {