Added custom mailer selection.
Refactored custom mailer selection.
Added tests for custom mailer selection.
Update Devise dependency to ~> 3.2
Token authenticatable strategy has been removed in Devise 3.2.0
Merge pull request #39 from baschtl/add-support-for-multiple-mailers

Add support for multiple mailers
Merge pull request #43 from rymai/update-devise-dependency

Update Devise dependency to ~> 3.2
bump to 0.9.0 and update changelog