Determine the current active version on the server
    
    Just examine the which environment is symlinked

def active_version():
    """
    Determine the current active version on the server
    
    Just examine the which environment is symlinked
    """
    
    link = '/'.join([deployment_root(),'env',env.project_name])
    if not exists(link): return None
    active = os.path.split(run('ls -al '+link).split(' -> ')[1])[1]
    return active