mark optional env variables

.example.env

@@ -1,21 +1,19 @@
-# App port to run on
+# Optional - App port to run on
 PORT=3000
 
-# The name of the site where Kutt is hosted
+# Optional - The name of the site where Kutt is hosted
 SITE_NAME=Kutt
 
-# The domain that this website is on
+# Optional - The domain that this website is on
 DEFAULT_DOMAIN=localhost:3000
 
-# A passphrase to encrypt JWT. Use a random long string.
+# Required - A passphrase to encrypt JWT. Use a random long string
 JWT_SECRET=
 
-# Database client. Available clients for the supported databases:
+# Optional - Database client. Available clients for the supported databases:
 # pg | pg-native | sqlite3 | better-sqlite3 | mysql | mysql2 | oracledb | tedious
 DB_CLIENT=sqlite3
-# SQLite database file name. Only if you use SQLite.
-DB_FILENAME=data
-# SQL database credential details. Only if you use Postgres or MySQL.
+# SQL database credential details, only if you use Postgres or MySQL
 DB_HOST=localhost
 DB_PORT=5432
 DB_NAME=kutt
@@ -67,7 +65,7 @@ MAIL_PASSWORD=
 # Optional - Enable rate limitting for some API routes
 ENABLE_RATE_LIMIT=false
 
-# Optional - The email address that will receive submitted reports.
+# Optional - The email address that will receive submitted reports
 REPORT_EMAIL=
 
 # Optional - Support email to show on the app