Using ruby and graphviz on heroku with heroku-buildpack-multi -

i'm trying deploy app on heroku. use declarative_authorization graphical visualisation.

i installed https://github.com/ddollar/heroku-buildpack-multi heroku config:set buildpack_url=https://github.com/ddollar/heroku-buildpack-multi , created .buildpacks with:

https://github.com/stigkj/heroku-buildpack-graphviz.git https://github.com/heroku/heroku-buildpack-ruby.git 

building works fine:

-----> fetching custom git buildpack... done -----> multipack app detected =====> downloading buildpack: https://github.com/stigkj/heroku-buildpack-graphviz.git =====> detected framework: graphviz -----> fetching , installing graphviz        grapvhiz installed =====> downloading buildpack: https://github.com/heroku/heroku-buildpack-ruby.git =====> detected framework: ruby/rails -----> using ruby version: ruby-1.9.3 

but when access graph:

errno::enoent in authorizationrulescontroller#graph no such file or directory - dot -q -tsvg 

what correct path?

use https://github.com/gokceneraslan/heroku-buildpack-graphviz instead of https://github.com/stigkj/heroku-buildpack-graphviz.git.

then, add configuration:

heroku config:add path:/usr/local/bin:/usr/bin:/bin:/app/bin 

source: https://github.com/pygram/pygram#deployment-on-heroku