Asked

How do I start on building a newsletter on Rails?

I want people to click subscribe w/ email so I can inform them when my app is launching soon.

Maker from USA
Maker of WIP amongst other things.

As discussed in the chat, the easiest way seems to use a hosted newsletter service such as MailChimp and just embed their signup form. No need to custom build something for Rails, unless you need deeper integration.

Maker of WIP amongst other things.

Also, WIP now has a prototype available for signup forms for your products. For example:

wip.chat/products/1725/subscr…

It's not possible to embed it on your own site, or host it on your own domain. But let me know what you'd like and I might add it.

https://montel.io (not the US TV host)

Another option is PH's Ship which adds social proof and 1 click subscribe for Product Hunt users. Might be a good fit if you want to launch there, and you can export the list to Mailchimp to send your own emails.