What gems do I have to use to let users sign in with their Twitter account?

Today, there are few authentication gems such as Twitter(http://ift.tt/mTeX1b)

Supposing that I have posts table, which has a field named "username". Then I want to insert the value of usernames of their twitter accounts to it.

How can I design my system structure and what gems I have to use to realize this procedure below?

1. 
   

   I sign in with my twitter account ID "test_john".

   
   


2. 
   

   After sign in, I post a comment "hello"

   
   


3. 
   

   New comment record will be created and these values will be inserted to each

   
   

   comments.username <= test_john comments.body <= hello

   
   

Can I do this without using Devise or OmniAuth or something like these authentication gems? or Do I have to use them anyway if I'm doing this?

What gems do I need at least?