Change case of alert json to initial lower letter.

This is more in line with common practice,
and with the webhook in alertmanager this will
be more directly exposed to users.

notification/notification.go

@@ -143,14 +143,14 @@ func (n *NotificationHandler) sendNotifications(reqs NotificationReqs) error {
 	alerts := make([]map[string]interface{}, 0, len(reqs))
 	for _, req := range reqs {
 		alerts = append(alerts, map[string]interface{}{
-			"Summary":     req.Summary,
-			"Description": req.Description,
-			"Labels":      req.Labels,
-			"Payload": map[string]interface{}{
-				"Value":        req.Value,
-				"ActiveSince":  req.ActiveSince,
-				"GeneratorURL": req.GeneratorURL,
-				"AlertingRule": req.RuleString,
+			"summary":     req.Summary,
+			"description": req.Description,
+			"labels":      req.Labels,
+			"payload": map[string]interface{}{
+				"value":        req.Value,
+				"activeSince":  req.ActiveSince,
+				"generatorURL": req.GeneratorURL,
+				"alertingRule": req.RuleString,
 			},
 		})
 	}

notification/notification_test.go

@@ -81,7 +81,7 @@ func TestNotificationHandler(t *testing.T) {
 			// Correct message.
 			summary:     "Summary",
 			description: "Description",
-			message:     `[{"Description":"Description","Labels":{"instance":"testinstance"},"Payload":{"ActiveSince":"0001-01-01T00:00:00Z","AlertingRule":"Test rule string","GeneratorURL":"prometheus_url","Value":"0.3333333333333333"},"Summary":"Summary"}]`,
+			message:     `[{"description":"Description","labels":{"instance":"testinstance"},"payload":{"activeSince":"0001-01-01T00:00:00Z","alertingRule":"Test rule string","generatorURL":"prometheus_url","value":"0.3333333333333333"},"summary":"Summary"}]`,
 		},
 	}