Fix ordering issues with student waitlist rsvps

* student_waitlist_rsvps is now always ordered by waitlist_position
* waitlist on the Event Show page shows the real waitlist_position
instead of the fetched rsvp index (though they should now be the same)
* Reload event in-between destroying an rsvp and reordering waitlist,
otherwise the student_rsvps_count isn't reloaded and no-one is promoted
* Don't use find_each in reorder_waitlist!, because it
apparently doesn't respect order in Rails 4.1

app/controllers/rsvps_controller.rb

@@ -65,7 +65,7 @@ def update
   def destroy
     Rsvp.transaction do
       @rsvp.destroy
-      @event.reorder_waitlist!
+      @event.reload.reorder_waitlist!
     end
     redirect_to events_path, notice: "You are now no longer signed up for #{@event.title}"
   end

app/models/event.rb

@@ -20,7 +20,7 @@ class Event < ActiveRecord::Base
   has_many :attendee_rsvps,  -> { where(role_id: [Role::STUDENT.id, Role::VOLUNTEER.id], waitlist_position: nil) }, class_name: 'Rsvp', inverse_of: :event
 
   has_many :student_rsvps, -> { where(role_id: Role::STUDENT.id, waitlist_position: nil) }, class_name: 'Rsvp', inverse_of: :event
-  has_many :student_waitlist_rsvps, -> { where("role_id = #{Role::STUDENT.id} AND waitlist_position IS NOT NULL") }, class_name: 'Rsvp', inverse_of: :event
+  has_many :student_waitlist_rsvps, -> { where("role_id = #{Role::STUDENT.id} AND waitlist_position IS NOT NULL").order(:waitlist_position) }, class_name: 'Rsvp', inverse_of: :event
   has_many :students, through: :student_rsvps, source: :user, source_type: 'User'
   has_many :legacy_students, through: :student_rsvps, source: :user, source_type: 'MeetupUser'
 
@@ -237,14 +237,14 @@ def reorder_waitlist!
     Rsvp.transaction do
       unless at_limit?
         number_of_open_spots = student_rsvp_limit - student_rsvps_count
-        to_be_confirmed = student_waitlist_rsvps.order(:waitlist_position).limit(number_of_open_spots)
+        to_be_confirmed = student_waitlist_rsvps.limit(number_of_open_spots)
         to_be_confirmed.each do |rsvp|
           rsvp.promote_from_waitlist!
         end
       end
 
       index = 1
-      student_waitlist_rsvps.order(:waitlist_position).find_each do |rsvp|
+      student_waitlist_rsvps.reload.each do |rsvp|
         rsvp.update_attribute(:waitlist_position, index)
         index += 1
       end

app/views/events/show.html.erb

@@ -123,8 +123,8 @@
     <% if @event.student_waitlist_rsvps.any? %>
       <h3><%= @event.student_waitlist_rsvps.length %> waitlisted!</h3>
       <ul class="attendees">
-        <% @event.student_waitlist_rsvps.each_with_index do |rsvp, ix| %>
-          <li class='attendee'><%= render 'shared/viewed_gravatars', :email => rsvp.user.email %><%= link_to rsvp.user.full_name, rsvp.user.profile_path %><span class='waitlist-number pull-right'>#<%= ix + 1 %></span></li>
+        <% @event.student_waitlist_rsvps.each do |rsvp| %>
+          <li class='attendee'><%= render 'shared/viewed_gravatars', :email => rsvp.user.email %><%= link_to rsvp.user.full_name, rsvp.user.profile_path %><span class='waitlist-number pull-right'>#<%= rsvp.waitlist_position %></span></li>
         <% end %>
       </ul>
     <% end %>

spec/models/event_spec.rb

@@ -430,11 +430,11 @@ def add_session_rsvp(rsvp, session, checked_in)
     end
 
     it "returns only confirmed rsvps in #student_rsvps" do
-      @event.student_rsvps.should == [@confirmed_rsvp]
+      @event.student_rsvps.reload.should == [@confirmed_rsvp]
     end
 
     it "returns only waitlisted rsvps in #student_waitlist_rsvps" do
-      @event.student_waitlist_rsvps.should == [@waitlist_rsvp]
+      @event.student_waitlist_rsvps.reload.should == [@waitlist_rsvp]
     end
   end