Password protects pages simply with rails - what should I do?

Now I am at level 7 of the Hartl rails tutorials and I'm starting to think about my application in deployment. This is an application that allows approximately 12 social workers to communicate together and privately. Thus, I need to protect it with a password.

However, it should also be easy to use, very easy to use. Some of these people have not used a computer before, and upon logging in and registering, they would have completely disabled them.

So I want to create a landing page where they have to enter a password (the same password for everyone), then it redirects to the "talk page". My first idea was to use some obfuscated javascript so that when entering the password it redirects them to the discussion pages, but this is not very safe.

Can anyone recommend me a better way to do this on rails? Ideally, they will only need to enter it once, and then it will automatically authenticate them for all pages (by setting a cookie?), And everyone who tries to access the page directly will be redirected to the authentication page.

Greetings in advance