feat: able to send alert message via message pusher (close #993)

common/message/main.go

@@ -0,0 +1,22 @@
+package message
+
+import (
+	"fmt"
+	"github.com/songquanpeng/one-api/common/config"
+)
+
+const (
+	ByAll           = "all"
+	ByEmail         = "email"
+	ByMessagePusher = "message_pusher"
+)
+
+func Notify(by string, title string, description string, content string) error {
+	if by == ByEmail {
+		return SendEmail(title, config.RootUserEmail, content)
+	}
+	if by == ByMessagePusher {
+		return SendMessage(title, description, content)
+	}
+	return fmt.Errorf("unknown notify method: %s", by)
+}