Implement track scheduling

Add track association to schedule
Show schedules in admin sidebar to track organizers
Allow track organizers to manage the schedules of their tracks
Don't allow self-organized track events to be dragged or unscheduled in
a conference schedule
Make scheduled events of self-organized tracks appear semitransparent in
conference schedules
Make the rooms of confirmed self_organized tracks appear semitransparent
and don't allow events to be scheduled to it in the conference schedules
during the dates of its track
Create admin/SchedulesController#new action
Add a button in admin/Schedules#index to create schedules for tracks
Add self_organized scope to Track
Modify Schedules#show to handle track schedules and show a unified
schedule
Allow track organizers to create new schedules for their tracks
Correctly identify scheduled and unscheduled events in Schedules#events
Fix Event#room and Event#time for when the event is scheduled in a track
schedule
Modify Program#selected_event_schedules to include the event_schedules
of selected track schedules
Modify Track#revoke_role_and_cleanup to destroy the track's schedules
and revert its events' state to new
Add tabs for conference and track schedules in admin/Schedules#index
Add button to Create/Show a tracks schedule in Tracks#index and #show
Fix concurrent_events in application_helper because of changes in
Program#selected_event_schedules
Do not take into account cfp_active in Event#valid_track
Modify EventsController#get_tracks accordingly
Enforce cfp_active of track to be enabled for proposals in
ProposalsController#create and #update
Add support for multiple schedules per track
Add selected_schedule_id to Track
Load EventSchedules of selected track schedules for conference schedules
in admin/SchedulesController#show
Modify SchedulesController#show to take into account only the selected
track schedules
Create Event#selected_schedule_id and use it in Event#scheduled? and
Event#time
Validate that an EventSchedule for an event of a self-organized track
belongs to one of the track's schedules
Add 'Manage' button in Tracks#index, #show that sends you to the admin
side of things
Add admin/TracksController#update_selected_schedule to update the
selected_schedule_id of tracks

app/views/admin/tracks/index.html.haml

@@ -63,9 +63,19 @@
               .btn-group{role: "group"}
                 - if can? :edit, track
                   = link_to 'Edit', edit_admin_conference_program_track_path(@conference.short_title, track), class: 'btn btn-primary'
+                  - special_style = true
                 - if can? :destroy, track
                   = link_to 'Delete', admin_conference_program_track_path(@conference.short_title, track), method: :delete, class: 'btn btn-danger',
                   data: { confirm: "Do you really want to delete #{track.name}? Attention: This track will be removed from all Events that have it set" }
+                - if track.self_organized?
+                  - if track.selected_schedule
+                    - if can? :show, track.selected_schedule
+                      = link_to 'Show Schedule', admin_conference_schedule_path(@conference.short_title, track.selected_schedule),
+                      class: 'btn btn-default'
+                  - elsif can? :create, @program.schedules.build(track: track)
+                    = button_to 'Create Schedule', admin_conference_schedules_path(@conference.short_title),
+                    form: { class: 'btn', style: 'padding: 0px 0px; margin-top: -1px;' }, class: 'btn btn-default',
+                    style: ('border-top-left-radius: 0; border-bottom-left-radius: 0;' if special_style), params: { 'schedule[track_id]' => track.id }
 .row
   .col-md-12.text-right
     = link_to 'New Track', new_admin_conference_program_track_path(@conference.short_title), class: 'btn btn-success'