Add required label "alertname" to POST-example (#1254)
Add required label "alertname" to POST-example (#1254)

We figured out that the label 'alertname' is required to get a proper response from AlertManager.

Signed-off-by: Decker, Stefan <6baf7d1a5dfd4581e25150d7124250fce7cdd4ce@gdata.de>
prometheus/docs,prometheus/docs,prometheus/docs