add password max length 16 to register

app/models/user.rb

@@ -666,6 +666,10 @@ class User < ApplicationRecord
     if password.present? && password.size < MIX_PASSWORD_LIMIT && !User.current.admin?
       raise("密码长度不能低于#{MIX_PASSWORD_LIMIT}位")
     end
+
+    if password.present? && password.size > 16
+      raise('密码长度不能超过16位')
+    end
   end
 end