Add Set Up Domain For Hatchbox Rails App as a devops TIL

devops/set-up-domain-for-hatchbox-rails-app.md

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+# Set Up Domain For Hatchbox Rails App
+
+When we deploy a Rails app with [Hatchbox](https://hatchbox.io), we are given
+an internal URL for publicly accessing our app. It is something like
+`https://123abc.hatchboxapp.com`. That's useful as we are getting things up and
+running, but eventually we want to point our own domain at the app.
+
+The first step is to tell Hatchbox what domain we are going to use.
+
+From our app's _Domain & SSL_ page we can enter a domain into the _Add A
+Domain_ input. For instance, I have the
+[visualmode.dev](https://visualmode.dev) domain and I want the
+[still.visualmode.dev](https://still.visualmode.dev) subdomain pointing at my
+Rails app. I submit the full name `still.visualmode.dev` and I get an _A
+Record_ ipv4 address (e.g. `23.12.234.82`).
+
+The second step is to configure a DNS record with our domain registrar.
+
+From the DNS settings of our registrar (e.g. Cloudflare) we can add an _A
+Record_ where we specify the name (e.g. `still`) and then include the ipv4
+address provided by Hatchbox. We can save this and wait a minute for it to
+propagate.
+
+And soon enough we can visit our Rails app at the custom domain.