diff --git a/backend-user/prisma/schema.prisma b/backend-user/prisma/schema.prisma
index 22a25ca..e8b6aeb 100644
--- a/backend-user/prisma/schema.prisma
+++ b/backend-user/prisma/schema.prisma
@@ -12,7 +12,7 @@ datasource db {
 
 model User {
   id         String  @id @default(cuid())
-  username   String
+  username   String  @unique
 
   oauth_id_42     String? @unique
   oauth_id_github String? @unique
@@ -23,4 +23,4 @@ model Follow {
 	id		String @id @default(cuid())
 	followerId	String
 	followingUsername String
-}
\ No newline at end of file
+}