Format text in forums (enter, bold,...)

I have forums in my web. I have a field in my database in my posts table
that is a textarea.
I would like to save things like press enter or use bold when I write a
message in the forum, but it is not possible only with what an scaffold
gives.
I think there are some javascripts that can help. Which is the best
idea?

Thanks a lot for helping me.

pode tentar colocar tinymce ou xinha. são 2 WYSIWYG.

Sorry, sleepy friday, need coffee:

You could try to use tinymce or xinha. these are both WYSIWYG editors.

Look at Textile or Markdown to make it really simple. I think there
might be a javascript editor to add the tags for you, but I would
recommend one of those two for simplicity's sake.