Ruby button action

I have a method in a controller file that I want activated only when a
button is pressed. That what i do

#index.html.erb#

<%= button_to ‘Export POINT’, :controller => ‘my_controller’, :action =>
‘create_file_txt’ %>

#my_controller.erb#

def create_file_txt
.
.
end

#init.rb#

permission :view_button_exp, {:controller => :my_controller, :action =>
:create_file_txt}, :require => :member

It’s not working, have i an erreur ??

Thanks