remove env var

Author: chad-syntax

pages/installation/railway.mdx

@@ -27,7 +27,6 @@ The environment variables should be already set up in the template, only listing
 
 ```env
 PORT="5000" # instructs railway to connect the public domain to port 5000
-BACK_END_PORT="3000"
 IS_GENERAL="true"
 SKIP_CONFIG_CHECK="true"
 DATABASE_URL="${{Postgres.DATABASE_URL}}"