chore: add .env.schema value example

.env.schema

@@ -0,0 +1,14 @@
+# railway, fly.dev, heroku, vercel or any free service
+RAILWAY = sinkaroid
+
+# default port
+PORT = 3000
+
+# backend storage, default is redis, if not set it will consume memory storage
+REDIS_URL = redis://default:somenicepassword@redis-666.c10.us-east-6-6.ec666.cloud.redislabs.com:1337
+
+# ttl expire cache (in X hour)
+EXPIRE_CACHE = 1
+
+# you must identify your origin, if not set it will use default
+USER_AGENT = "lustpress/1.6.0 Node.js/16.9.1"