change rank function

src/backend/Components/User/UserManager.ts

         await this.admin
         .knex('users')
         .where({
-            user:user.username
+            username: user.username
         }).update({
             rank: rank
         })
         return await this.admin
         .knex('users')
         .where({
-            user: user.username
+            username: user.username
         }).first()
     }