The package currently relies on rebar3 to fetch webmachine and mochikit during
the build. So when building with git-buildpackage and pbuilder you have to
allow network access e.g. via:

    gbp buildpackage --git-pbuilder-options="--use-network yes" --git-dist=jessie  --git-no-pristine-tar

This builds a self contained application with minimal external dependencies.