Disallow self-follow

app/services/follow_service.rb

@@ -5,7 +5,7 @@ class FollowService < BaseService
   def call(source_account, uri)
     target_account = follow_remote_account_service.(uri)
 
-    return nil if target_account.nil?
+    return nil if target_account.nil? || target_account.id == source_account.id
 
     follow = source_account.follow!(target_account)