File creation in Rails

I am passing the contents of a textarea in my rails view to the server
by a POST call. How can I store the contents as a separate file, say
contents_userId.txt on my server and at the same time store my file in
database allowing me to access the various files a single user
has...or for any other purpose.

To access files in rails, you can use the Ruby File Class

http://ruby-doc.org/core/classes/File.html#M002579

You can put this into a method in the model. Then either call it
specifically from the controller, or use an after_update callback to
automatically create the file after the object has been saved to the
database

def save_file(filename)
   File.open "#{RAILS_ROOT}/tmp/#{filename}", 'w' do |f|
      f.write contents
   end
end

Tonypm