form partial for new and edit

_form.html.erb

# app/views/shared/_form.html.erb:
<%= form_for(@user, button_text) do |f| %>
  <%= render 'fields', :f => f %>
  <div class="actions">
    <%= f.submit button_text %>
  </div>
<% end %>

call from new.html.erb

# Now works when called from new.html.erb with either:
<%= render 'shared/form', :locals =>{:button_text => "Sign Up!"} %>
#or
<%= render 'shared/form', :button_text => "Sign Up!" %>

#(same for edit.html.erb, with a different button_text)