Remove foreman

Whether or not a developer wants to start their local processes with
`foreman` has no bearing on whether others working on the same code will
start it the same way. It's often inadvisable, therefore, to add foreman
to a project's `Gemfile`.

bundler-exec.sh

@@ -58,7 +58,6 @@ chef-shell
 chef-solo
 cucumber
 foodcritic
-foreman
 guard
 haml
 html2haml