cantino/huginn — pull request #431 by knu (2014-08-08 12:46:01+00:00)
Title: Enable Graphviz on Heroku.

Graphviz is installed via heroku-buildpack-graphviz-src and the location
of dot(1) is automatically added to PATH.

There is also heroku-buildpack-graphviz-deb which should be easier to
install, but the Debian package installed has a font style problem.