Recently did some brief research about using scrum in Trello.
https://theagilecoder.wordpress.com/2013/11/11/how-to-set-up-trello-board-for-scrum/
https://blog.trello.com/how-to-scrum-and-trello-for-teams-at-work
https://screenful.com/trello/trello-sprint-burndown/
https://trello.com/b/WELsX9Hm/agile-board-example
Scrum in Trello