Improve @mention regex

app/models/account.rb

@@ -1,7 +1,7 @@
 class Account < ApplicationRecord
   include Targetable
 
-  MENTION_RE = /(?:^|\s|\.|>)@([a-z0-9_]+(?:@[a-z0-9\.\-]+)?)/i
+  MENTION_RE = /(?:^|[\s\.>*+])@([a-z0-9_]+(?:@[a-z0-9\.\-]+)?)/i
   IMAGE_MIME_TYPES = ['image/jpeg', 'image/png', 'image/gif'].freeze
 
   # Local users

app/services/process_hashtags_service.rb

@@ -4,7 +4,7 @@ class ProcessHashtagsService < BaseService
       tags = status.text.scan(Tag::HASHTAG_RE).map(&:first)
     end
 
-    tags.map(&:downcase).each do |tag|
+    tags.map(&:downcase).uniq.each do |tag|
       status.tags << Tag.where(name: tag).first_or_initialize(name: tag)
     end
   end