app/views/turns/new.html.erb
<h1>Turns#new</h1>
<%= form_for (@turn) do |f| %>
<%= f.label :start_date %><br/>
<%= f.date_field :start_date %><br/><br/>
<%= f.label :end_date %><br/>
<%= f.date_field :end_date %><br/><br/>
<%= hidden_field_tag :assignment_id, params[:assignment_id] %>
<%= hidden_field_tag :colony_id, params[:colony_id] %>
<%= f.submit %>
<% end %>