Add Subgroup-reference to participant

Rudimentary filtering in activity#show, needs more work and equivalent
in mobile view

app/assets/javascripts/activities.coffee

   clipboard = new Clipboard('.copy-reactions', {
     'text': clipreactions
   })
+  $('#subgroup_filter').on('change', (e) -> filterparticipants(e))
 
 @clipreactions = (trigger) ->
   id = trigger.dataset['activity']
     res.push(resp['unknown']['message'])
 
   res.join('\n')
+
+@filterparticipants = (e) ->
+  show = e.target.value
+  if (show != 'all')
+	  selector = "[data-subgroup-id=" + e.target.value + "]"
+	  $('.participant-row').hide()
+	  $(selector).show()
+  else
+    $('.participant-row').show()

app/controllers/activities_controller.rb

       .where(is_assignable: true)
       .order(name: :asc)
       .pluck(:name)
+    @subgroup_ids = @activity.subgroups
+      .order(name: :asc)
+      .pluck(:name, :id)
+    @subgroup_ids.prepend( ['*' , 'all'] )
   end
 
   # GET /activities/new

app/models/participant.rb

 
   belongs_to :person
   belongs_to :activity
+  belongs_to :subgroup, optional: true
 
   validates :person_id,
     uniqueness: {

app/models/subgroup.rb

 class Subgroup < ApplicationRecord
   belongs_to :activity
+  has_many :participants
 
   validates :name, presence: true, uniqueness: { scope: :activity, case_sensitive: false }
   validates :activity, presence: true

app/views/activities/show.html.haml

             emptytext: t('activities.participant.add_notes')
 
 .hidden-xs
-  %h2
-    = @num_participants
-    = t 'activities.participant.plural'
-    = render partial: "state_counts", locals: {counts: @counts}
+  .row
+    .col-md-6
+      %h2
+        = @num_participants
+        = t 'activities.participant.plural'
+        = render partial: "state_counts", locals: {counts: @counts}
+    .col-md-6
+      = select_tag(:subgroup_filter, options_for_select(@subgroup_ids), class: 'form-control')
 
   %table.table.table-bordered
     - @participants.each do |p|
-      %tr{class: p.row_class, data: {person_id: p.person.id, activity_id: @activity.id}}
+      %tr.participant-row{class: p.row_class, data: {person_id: p.person.id, activity_id: @activity.id, subgroup_id: p.subgroup_id}}
         %td
           = p.person.full_name
           - if p.is_organizer

db/migrate/20171001150124_add_subgroup_to_participants.rb

+class AddSubgroupToParticipants < ActiveRecord::Migration[5.0]
+  def change
+    add_reference :participants, :subgroup, foreign_key: true
+  end
+end

db/schema.rb

 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20171001124009) do
+ActiveRecord::Schema.define(version: 20171001150124) do
 
   create_table "activities", force: :cascade do |t|
     t.string   "name"
     t.text     "notes"
     t.datetime "created_at",   null: false
     t.datetime "updated_at",   null: false
+    t.integer  "subgroup_id"
     t.index ["activity_id"], name: "index_participants_on_activity_id"
     t.index ["person_id", "activity_id"], name: "index_participants_on_person_id_and_activity_id", unique: true
     t.index ["person_id"], name: "index_participants_on_person_id"
+    t.index ["subgroup_id"], name: "index_participants_on_subgroup_id"
   end
 
   create_table "people", force: :cascade do |t|