used http://stackoverflow.com/questions/9395970/how-to-submit-multiple-duplicate-forms-from-same-page-in-rails-preferably-wit

submit_multiple_forms_one_button.rb

#view

Who's In?                                                                                      
<table>
  <tr>
     <td><h4>Name</h4></td><td><h4>Email</h4></td><td><h4>Number of Voting Shares</h4></td><td>
       <%= form_tag(invites_path) do %>
         <% 3.times do %>
         <%= render 'invites/project_member_form' %>
       <% end %>
       <td><%= submit_tag 'Save' %></td><% end %>
 </table>
 
 #view partial
<tr><td><%= text_field_tag 'invite[][name]' %></td>
<td><%= email_field_tag 'invite[][email]' %></td>
<td><%= number_field_tag 'invite[][proposed_number_of_voting_shares]' %></td>
<td><%= number_field_tag 'invite[][proposed_number_of_non_voting_shares]' %></td></tr>

# controller
def create
  @invite_1 = Invite.new(params[:invite][0])
  @invite_2 = Invite.new(params[:invite][1])
  @invite_3 = Invite.new(params[:invite][2])
 
  respond_to do |format|
    if @invite_1.save | @invite_2.save | @invite_3.save                                      
      format.html { redirect_to agreement_draft_path, notice: 'Invite was successfully created.' }
      format.json { render json: @invite, status: :created, location: @invite }
    else
      format.html { render action: "new" }
      format.json { render json: @invite.errors, status: :unprocessable_entity }
    end
  end 
end