新增：新增反馈意见邮件回复功能

app/mailers/user_mailer.rb

@@ -1,6 +1,6 @@
 class UserMailer < ApplicationMailer
   # 注意：这个地方一定要和你的邮箱服务域名一致
-  default from: 'notification@trustie.org'
+  default from: 'admin@trustie.org'
 
   # 用户注册验证码
   def register_email(mail, code)
@@ -12,4 +12,8 @@ class UserMailer < ApplicationMailer
     @code = code
     mail(to: mail, subject: 'Gitink | 更改邮箱验证码')
   end
+
+  def feedback_email(mail, title, content)
+    mail(to: mail, subject: title, content_type: "text/html", body: content)
+  end
 end