init project

app/mailers/user_mailer.rb

@@ -0,0 +1,17 @@
+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'
+
+  # 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?
+  end
+end