Make server bind address configurable (#20)

Author: loganintech

src/main/java/me/lucko/luckperms/extension/rest/RestExtension.java

@@ -43,12 +43,13 @@ public RestExtension(LuckPerms luckPerms) {
     @Override
     public void load() {
         int port = RestConfig.getInteger("http.port", 8080);
+        String address = RestConfig.getString("http.address", "localhost");
 
         Thread thread = Thread.currentThread();
         ClassLoader previousCtxClassLoader = thread.getContextClassLoader();
         thread.setContextClassLoader(RestExtension.class.getClassLoader());
         try {
-            this.server = new RestServer(this.luckPerms, port);
+            this.server = new RestServer(this.luckPerms, address, port);
         } finally {
             thread.setContextClassLoader(previousCtxClassLoader);
         }

src/main/java/me/lucko/luckperms/extension/rest/RestServer.java

@@ -72,19 +72,19 @@ public class RestServer implements AutoCloseable {
     private final Javalin app;
     private final AutoCloseable routesClosable;
 
-    public RestServer(LuckPerms luckPerms, int port) {
+    public RestServer(LuckPerms luckPerms, String address, int port) {
         LOGGER.info("[REST] Starting server...");
 
         this.objectMapper = new CustomObjectMapper();
 
         this.app = Javalin.create(this::configure)
-                .start(port);
+                .start(address, port);
 
         this.setupLogging(this.app);
         this.setupErrorHandlers(this.app);
         this.routesClosable = this.setupRoutes(this.app, luckPerms);
 
-        LOGGER.info("[REST] Startup complete! Listening on http://localhost:" + port);
+        LOGGER.info(String.format("[REST] Startup complete! Listening on http://%s:%d", address, port));
     }
 
     @Override