fix README.rst
fix README.rst

0312birdzhang/alerta,mrkeng/alerta,skob/alerta,mrkeng/alerta,guardian/alerta,skob/alerta,mrkeng/alerta,guardian/alerta,skob/alerta,0312birdzhang/alerta,mrkeng/alerta,guardian/alerta,0312birdzhang/alerta,guardian/alerta,skob/alerta