Friendly urls for tracks

Don't use tracks ids in urls
Add short_name to tracks and use that in urls as the identifier

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

@@ -8,8 +8,9 @@
         Track
 .row
   .col-md-12
-    = semantic_form_for(@track, url: (@track.new_record? ? admin_conference_program_tracks_path : admin_conference_program_track_path(@conference.short_title, @track))) do |f|
+    = semantic_form_for(@track, url: (@track.new_record? ? admin_conference_program_tracks_path : admin_conference_program_track_path(@conference.short_title, @track.short_name))) do |f|
       = f.input :name
+      = f.input :short_name, hint: "A short and unique handle for the track, using only letters, numbers, underscores, and dashes. This will be used to identify the track in URLs etc. Example: 'my_awesome_track'", input_html: { required: 'required', pattern: '[a-zA-Z0-9_-]+', title: 'Only letters, numbers, underscores, and dashes.' }
       = f.input :color, input_html: {size: 6, type: 'color'}, required: true
       = f.input :description, input_html: {rows: 2, data: { provide: 'markdown-editable' } }, hint: markdown_hint
       = f.action :submit, as: :button, button_html: { class: 'btn btn-primary' }

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

@@ -9,6 +9,7 @@
     %table.table.table-hover#tracks
       %thead
         %th Name
+        %th Short name
         %th Description
         %th Color
         %th Actions
@@ -16,8 +17,10 @@
         - @tracks.each do |track|
           %tr
             %td
-              = link_to(admin_conference_program_track_path(@conference.short_title, track)) do
+              = link_to(admin_conference_program_track_path(@conference.short_title, track.short_name)) do
                 = track.name
+            %td
+              = track.short_name
             %td
               %p
                 = truncate(track.description)
@@ -26,9 +29,9 @@
                 = track.color
             %td
               .btn-group{role: "group"}
-                = link_to 'Edit', edit_admin_conference_program_track_path(@conference.short_title, track.id),
+                = link_to 'Edit', edit_admin_conference_program_track_path(@conference.short_title, track.short_name),
                 method: :get, class: 'btn btn-primary'
-                = link_to 'Delete', admin_conference_program_track_path(@conference.short_title, track.id),
+                = link_to 'Delete', admin_conference_program_track_path(@conference.short_title, track.short_name),
                 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" }
 .row

app/views/admin/versions/_object_desc_and_link.html.haml

@@ -94,7 +94,7 @@
   = 'track'
   - track = current_or_last_object_state(version.item_type, version.item_id)
   = link_if_alive version, track.name,
-          admin_conference_program_track_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
+          admin_conference_program_track_path(conference_id: Conference.find(version.conference_id).short_title, id: track.try(:short_name))
 
 - when 'EventType'
   = 'event type'