To restrict access to your publication, and prevent it from being publicly accessible, set a site-wide password. While your site is marked as private, visitors will need to enter a password to view content.
To require a password to view your publication, follow the steps below.
Log in to your publication at http://subdomain.ghost.io/ghost/signin
Go to General from the admin menu
Make this site private, check the box to enable password protection. You may use a custom password, or the one generated for you.
Click Save settings
Note: All search engine optimization and social features(including the RSS feed) will be disabled when a publication is marked as private.