diff --git a/.gitignore b/.gitignore
index e021bb8..6855e13 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ __pycache__
 nohup.out
 app.pid
 *.log
+.env
diff --git a/app/config.py b/app/config.py
index 1561f9b..d5e0269 100644
--- a/app/config.py
+++ b/app/config.py
@@ -20,8 +20,8 @@ class Config:
     SECRET_KEY = get_secret_key()
     SQLALCHEMY_DATABASE_URI = "sqlite:////app/instance/db.sqlite"
     UPLOAD_FOLDER = "/app/sites"
-    SERVER_NAME = "tinysite.cloud"
-    SESSION_COOKIE_DOMAIN = ".tinysite.cloud"
+    SERVER_NAME = os.environ.get("SERVER_NAME", "tinysite.cloud")
+    SESSION_COOKIE_DOMAIN = "." + SERVER_NAME
     SESSION_COOKIE_NAME = "tinysite_session"
     SESSION_COOKIE_HTTPONLY = True
     SESSION_COOKIE_SECURE = True
diff --git a/app/upload.py b/app/upload.py
index 9249c8b..fc538ee 100644
--- a/app/upload.py
+++ b/app/upload.py
@@ -46,6 +46,11 @@ def handle_upload(current_user, site_name, subdomain, files):
         flash("Invalid subdomain format", "error")
         return redirect(url_for("main.dashboard"))
 
+    # Check for reserved subdomains
+    if subdomain in Config.RESERVED_SUBDOMAINS:
+        flash(f"The subdomain '{subdomain}' is reserved", "error")
+        return redirect(url_for("main.dashboard"))
+
     if not site_name or not subdomain:
         flash("Name and subdomain required", "error")
         return redirect(url_for("main.dashboard"))
diff --git a/docker-compose.yml b/docker-compose.yml
index b19c913..87d9349 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -1,19 +1,18 @@
 services:
-  app:
-    build: .
-    ports:
-      - "5121:5121"
-    networks:
-      - static
-    volumes:
-      - instance:/app/instance
-      - sites:/app/sites
-    environment:
-      - FLASK_ENV=production
+    app:
+        build: .
+        ports:
+            - "5121:5121"
+        networks:
+            - static
+        volumes:
+            - instance:/app/instance
+            - sites:/app/sites
+        env_file: .env
 
 networks:
-  static:
+    static:
 
 volumes:
-  instance:
-  sites:
\ No newline at end of file
+    instance:
+    sites: