In the workflow part, for the Code Signing & File part for Android the link for the tutorial is dead :
http://devcenter.bitrise.io/tutorials/create-signed-apk-on-bitrise/
Fixed, will be deployed into production in ~20 mins.
Thanks for reporting @z17jdavi!
For reference, the right link is: http://devcenter.bitrise.io/android/code-signing/