demo won't deploy to heroku

[asecondwill]

-----> Ruby app detected
-----> Compiling Ruby/Rails
!
! An error occurred while installing ruby-2.1.2
!
! Heroku recommends you use the latest supported Ruby version listed here:
! https://devcenter.heroku.com/articles/ruby-support#supported-runtimes
!
! For more information on syntax for declaring a Ruby version see:
! https://devcenter.heroku.com/articles/ruby-versions
!
! Note: Only the most recent version of Ruby 2.1 is supported on Cedar-14
!
! Debug InformationCommand: 'set -o pipefail; curl -L --fail --retry 5 --retry-delay 1 --connect-timeout 3 --max-time 30 https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/heroku-16/ruby-2.1.2.tgz -s -o - | tar zxf - ' failed unexpectedly:
!
! gzip: stdin: unexpected end of file
! tar: Child returned status 1
! tar: Error is not recoverable: exiting now
!
! Push rejected, failed to compile Ruby app.
! Push failed

[MrRezaque]

+1, same issue.