update env example with proposed config changes

.env.example

@@ -1,3 +1,22 @@
 # Do not use quotes, make will scream at you
+
+# Database Configuration
 DATABASE_URL=postgres://user:password@localhost/termcloud
+
+# Server Configuration
 PORT=8080
+STORAGE_DIR=storage
+MAX_FILE_SIZE_MB=100
+RATE_LIMIT=20.0
+CORS_ORIGINS=*
+GZIP_LEVEL=5
+
+# Database Pool Configuration
+DB_MAX_CONNECTIONS=100
+DB_MIN_CONNECTIONS=10
+DB_CONN_LIFETIME=1h
+DB_CONN_IDLE_TIME=1m
+DB_HEALTH_CHECK_PERIOD=5s
+
+# User Defaults
+DEFAULT_STORAGE_LIMIT_GB=1