Fix incorrect upstream_target config

apps/api/src/services/nginx/info/upstream_target.rs

@@ -130,7 +130,7 @@ impl From<UpstreamTargetCreateInfo> for upstream_target::ActiveModel {
 impl NginxConfigProvider for UpstreamTargetInfo {
     fn to_nginx_config(&self, indent: Option<usize>) -> String {
         format!(
-            "{}:{} weight={}{}{}",
+            "server {}:{} weight={}{}{};",
             self.target_host,
             self.target_port,
             self.weight,