Docs: Add SMTP config

Author: andrew-opensignlabs

.env.example

@@ -42,11 +42,15 @@ DO_REGION=us-west
 # Set this to true id you are using local storage instead of s3 compatible storage
 # USE_LOCAL=TRUE
 
-
-# Email mailgun config (The app will not initialize if any of these 3 variables are not set) *********************************************************************************************************************
-MAILGUN_API_KEY=
+# Email mailgun or set SMTP_ENABLE true to use SMTP config (The app will not initialize if any of these 3 variables are not set) *********************************************************************************************************************
+MAILGUN_API_KEY=XXXXX
 MAILGUN_DOMAIN=mail.yourdomain.com
 MAILGUN_SENDER=[email protected]
+SMTP_ENABLE=
+SMTP_HOST=
+SMTP_PORT=
+SMTP_USER_EMAIL=
+SMTP_PASS=
 
 # Base64 encoded PFX or p12 document signing certificate file *********************************************************************************************************************
 PFX_BASE64=