Rails 6.1 deprecation warning

[lubosch]

this issue: rails/rails#36546 is caused by this gem because of

# /lib/railgun/railtie.rb
ActionMailer::Base.add_delivery_method :mailgun, Railgun::Mailer

rails/rails#36546 (comment)

and it can be fixed I guess by rails/rails#36546 (comment)

ActiveSupport.on_load(:action_mailer) do
  add_delivery_method :mailgun, Railgun::Mailer
end

[cgunther]

#162 is an attempt to address this.

[lubosch]

official response from mailgun support:

We do not have an exact date as this is something that is being worked on. Our goal is to have it done in roughly the next few months

So either don't use mailgun, this gem, fix it yourself or don't upgrade rails next few months ...

[zokioki]

Looks like a fix for this was just introduced in v1.2.4:
https://github.com/mailgun/mailgun-ruby/blob/v1.2.4/lib/railgun/railtie.rb#L5-L8.