make code configurable

src/config.ts

@@ -1,6 +1,7 @@
 export const Config = {
   jwt_secret:
+    process.env.JWT_SECRET ||
     "T4kE6/tIqCVEZYg9lwsqeJjYfOoXTXSXDEMyParsJjj57CjSdkrfPOLWP74/9lJpcBA=",
-  token_duration: "365d",
-  api_url: "http://localhost:3000",
+  token_duration: process.env.TOKEN_DURATION || "365d",
+  api_url: process.env.API_URL || "http://localhost:3000",
 };