feat: add CLI flags to app

- implement command-line flags for listen address and port
- add usage section to README

🤖

pkg/models/config.go

@@ -8,6 +8,6 @@ type GoTomatoTimerConfig struct {
 }
 
 type GoTomatoServerConfig struct {
-	ListenAddress string `json:"listenAddress"`
-	ListenPort    int    `json:"listenPort"`
+	ListenAddress string `json:"listenAddress, default:"0.0.0.0"`
+	ListenPort    int    `json:"listenPort, default:8080"`
 }