Extend README by config example
Extend README by config example

novilabs/alertmanager,ericgerling/alertmanager,pdf/alertmanager,brancz/alertmanager,Aloomaio/alertmanager,GoogleCloudPlatform/alertmanager,MonsantoCo/alertmanager,tyrken/alertmanager,Kellel/alertmanager,tbouvet/alertmanager,tyrken/alertmanager,brunoqc/alertmanager,novilabs/alertmanager,tinytub/alertmanager,MonsantoCo/alertmanager,tbouvet/alertmanager,GoogleCloudPlatform/alertmanager,joehandzik/alertmanager,Kellel/alertmanager,tyrken/alertmanager,pdf/alertmanager,pdf/alertmanager,GoogleCloudPlatform/alertmanager,prometheus/alertmanager,brunoqc/alertmanager,joehandzik/alertmanager,prometheus/alertmanager,brunoqc/alertmanager,novilabs/alertmanager,tbouvet/alertmanager,sarathsp06/alertmanager,tinytub/alertmanager,pdf/alertmanager,brancz/alertmanager,MonsantoCo/alertmanager,tinytub/alertmanager,novilabs/alertmanager,sarathsp06/alertmanager,brancz/alertmanager,prometheus/alertmanager,tyrken/alertmanager,ericgerling/alertmanager,ericgerling/alertmanager,prometheus/alertmanager,brancz/alertmanager,GoogleCloudPlatform/alertmanager,Kellel/alertmanager,brunoqc/alertmanager,joehandzik/alertmanager,sarathsp06/alertmanager,Aloomaio/alertmanager,Aloomaio/alertmanager,MonsantoCo/alertmanager