Alert user when they have no connection and allow them to retry

[lmerriam]

Because this app serves a website, it does not work without an internet connection. We need to detect when the app cannot connect to the server, so we can tell the user to check their internet connection and try again.

Here are the PSDs: https://www.dropbox.com/sh/y9dwbto9dlwobmn/AACwceTLeN2EXn7gR2P38U2za?dl=0

"Try again" would ideally refresh the current page, so that if the user is in the middle of a session they will return to the URL they attempted to load when they lost connection. Please let me know if this is complicated.