Restore a Cozy
        backup_file: path to .tar.gz

def restore(backup_file):
    '''
        Restore a Cozy
        backup_file: path to .tar.gz
    '''
    if not os.path.isfile(backup_file) and not os.path.islink(backup_file):
        print 'Missing backup file: {}'.format(backup_file)
    else:
        couchdb_path = _get_couchdb_path()

        print 'Restore Cozy:'
        cmd = 'supervisorctl stop cozy-controller ; sleep 10'
        cmd += ' ; service couchdb stop ; service nginx stop'
        cmd += ' ; rm -rf {couchdb_path}/.cozy_design'
        cmd += ' {couchdb_path}/_replicator.couch'
        cmd += ' ; tar xvzf {backup_file} -C /'
        cmd += ' ; service couchdb start ; service nginx start'
        cmd = cmd.format(backup_file=backup_file, couchdb_path=couchdb_path)
        helpers.cmd_exec(cmd, show_output=True)
        helpers.wait_couchdb(10)
        cmd = 'supervisorctl start cozy-controller'
        helpers.cmd_exec(cmd, show_output=True)