FIX 完善邮箱注册发送邮件功能

app/mailers/user_mailer.rb

@@ -1,17 +1,10 @@
 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: 'educoder@trustie.org'
+  default from: 'notification@gitlink.org.cn'
 
   # 用户注册验证码
   def register_email(mail, code)
     @code = code
-    mail(to: mail, subject: '验证你的电子邮件')
-  end
-
-  # 课堂讨论区的邮件通知
-  def course_message_email(mail, message_id)
-    @message = Message.find_by(id: message_id)
-    @course = @message&.board&.course
-    mail(to: mail, subject: '课堂发布了新的帖子') if @message.present? && @course.present?
+    mail(to: mail, subject: 'GitLink | 注册确实开源邮箱验证')
   end
 end