improved the error handling

src/controller/dns_controller.rs

@@ -0,0 +1,13 @@
+use crate::controller::Controller;
+
+impl Controller {
+    pub async fn add_domain_to_dns(&self, domain: &str) -> Result<(), Box<dyn std::error::Error>> {
+        self.dns_manager.add_domain(domain, self.pub_addr).await?;
+        Ok(())
+    }
+
+    pub async fn del_domain_to_dns(&self, domain: &str) -> Result<(), Box<dyn std::error::Error>> {
+        self.dns_manager.del_domain(domain).await?;
+        Ok(())
+    }
+}