Preserve environment config

flake.nix

@@ -75,7 +75,7 @@
                 DynamicUser = "yes";
                 PrivateTmp = "yes";
                 Environment = [
-                  "PORT=${toString cfg.port}"
+                  "ROCKET_PORT=${toString cfg.port}"
                 ];
               };
             };

src/main.rs

@@ -5,6 +5,7 @@ use config::Config;
 use governor::{clock::DefaultClock, state::keyed::DashMapStateStore, Quota, RateLimiter};
 use mail_send::{SmtpClientBuilder, Credentials};
 use rocket::data::{Limits, ToByteUnit};
+use rocket::config::Config as RConfig;
 
 mod config;
 mod endpoints;
@@ -49,7 +50,7 @@ fn rocket() -> _ {
     let rocket_conf = rocket::config::Config {
         limits: Limits::default()
             .limit("json", 2.kibibytes()),
-        ..Default::default()
+        ..RConfig::from(RConfig::figment())
     };
             
     rocket::custom(rocket_conf)