fix port mapping in vagrantfile

Vagrantfile

@@ -40,13 +40,15 @@
 Vagrant.configure("2") do |config|
   config.vm.box = "ubuntu/focal64"
 
+  port = ENV['BUBBLE_PORT'] || 8090
+
   # You can access the launcher on port 8090 (or BUBBLE_PORT) but only on 127.0.0.1
   # If you want to allow outside access to port 8090 (listen on 0.0.0.0), use the version below
   if not ENV.include? 'BUBBLE_PUBLIC_PORT' or ENV['BUBBLE_PUBLIC_PORT'] == 'false' then
-      config.vm.network "forwarded_port", guest: 8090, host: ENV['BUBBLE_PORT'] || 8090, host_ip: "127.0.0.1"
+      config.vm.network "forwarded_port", guest: port, host: port, host_ip: "127.0.0.1"
   else
       # Anyone who can reach port 8090 on this system will be able to access the launcher
-      config.vm.network "forwarded_port", guest: 8090, host: ENV['BUBBLE_PORT'] || 8090
+      config.vm.network "forwarded_port", guest: port, host: port
   end
 
   # Update system
@@ -60,7 +62,7 @@ Vagrant.configure("2") do |config|
   # Get dependencies and build everything
   config.vm.provision :shell do |s|
       s.env = {
-        BUBBLE_PORT: ENV['BUBBLE_PORT'],
+        BUBBLE_PORT: port,
         LETSENCRYPT_EMAIL: ENV['LETSENCRYPT_EMAIL']
       }
       s.privileged = false