Rails subdomains with lvh.me
localhost does not behave like a real domain for subdomain testing, so Rails routes such as app.example.com are awkward to test locally.
lvh.me solves that by resolving to 127.0.0.1, which means you can use real-looking local subdomains like:
app.lvh.me:3000admin.lvh.me:3000
That makes it much easier to test Rails subdomain routing locally without editing /etc/hosts.