Rails: model validations and errors not appearing - ruby-on-rails

Question

I'm creating multiple objects from a single form:
def new
#opening_hour = []
7.times do
#opening_hour << OpeningHour.new
end
render :template => "stores/opening_hours/new"
end
def create
params["opening_hour = "].each do |hour|
if hour["day"] != "" || hour["closes"] != "" || hour["opens"] != ""
#res = OpeningHour.new(opening_hour_params(hour))
puts #res.errors unless #res.save
redirect_to(store_items_index_path)
return
end
end
end
and the form looks like this:
<%= form_tag store_opening_hours_create_path do %>
<% #opening_hour.each do |hour| %>
<%= fields_for 'opening_hour = []', hour do |p|%>
<% if #res.errors.any? %>
<div class="centerList">
<div id="error_explanation">
<h2><%= pluralize(#res.errors.count, "error") %> <%= t 'store_edit_account_errors' %></h2>
<% #res.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</div>
</div>
<% end %>
But after I click on submit... I get an error: undefined method 'errors' for nil:NilClass at this line <% if #res.errors.any? %>. If I delete the error part from the form then everything works fine and the all 7 objects get created. From my understanding this is happening because the value #res is nil... but not really sure how to make this work... any ideas??
Update 1
def new
#opening_hour = []
7.times do
#opening_hour << OpeningHour.new
end
render :template => "stores/opening_hours/new"
end
def create
params["opening_hour = "].each do |hour|
if hour["day"] != "" || hour["closes"] != "" || hour["opens"] != ""
#res = OpeningHour.new(opening_hour_params(hour))
if #res.success
format.html { redirect_to #res, notice: 'Hours were successfully created.' }
format.json { render :show, status: :ok, location: #res }
else
format.html { render :'stores/opening_hours/edit' }
format.json { render json: #res.errors, status: :unprocessable_entity }
end
end
end
end

Answer 1

Try instantiating it at the top of the create action. Probably it's not getting set as you think it is.
def create
#res = OpeningHour.new
# ...
end
You should also have to do something similar in the new action, #res is also not set there.

Answer 2

If you redirect, you trigger a new request where everything that happens before in memory is not persisted.
This is the reason why:
on success we redirect: everything went fine
on error, we render the form directly so it has the object with errors to display