Remove the rebar binary
Add .rebar in the .gitignore file
Use the installed rebar
Add a release to Fubar
Specify the parameters in the env of the application
Specify the configuration in the sys.config file
Fix the dependency cowboy
Add the compilation in the dependency of the release
Use the environment for the configuration
Because there is a bug with the release and the structure of the
project, we moved the source in apps/fubar. By the way we fix the release
and avoid to receive this kind of error:

ERROR: generate failed while processing fubar/rel:
{'EXIT',{{badmatch,{error,"fubar: Application version clash. Multiple directories contain version \"3.0.0\"."}},

Move the application fubar in its own apps/fubar directory.