Remove useless text from received mails via the email_reply_trimmer gem

plugins/messages/app/mail_receivers/messages_mail_receiver.rb

@@ -1,3 +1,5 @@
+require "email_reply_trimmer"
+
 class MessagesMailReceiver
 
   def self.regexp
@@ -37,6 +39,8 @@ class MessagesMailReceiver
       body = Nokogiri::HTML(body).text
     end
 
+    body = EmailReplyTrimmer.trim(body)
+
     message = user.send_messages.new body: body,
       group: original_message.group,
       private: original_message.private,