Can't rebuild app 'bundle exec rake db:migrate' failed

[tgxworld (Alan Tan)]

@Falco It looks like this line needs to be updated to maintain compatibility with the latest version of Discourse.

https://github.com/xfalcox/discourse-backups-to-dropbox/blob/2ea0e7a656d60da679bd2110a09308d19b56f0f5/plugin.rb#L7