Sort exercise collection items by position

app/models/exercise_collection.rb

@@ -2,6 +2,7 @@ class ExerciseCollection < ActiveRecord::Base
   include TimeHelper
 
   has_many :exercise_collection_items
+  alias_method :items, :exercise_collection_items
   has_many :exercises, through: :exercise_collection_items
   belongs_to :user, polymorphic: true
 

app/views/exercise_collections/show.html.slim

@@ -12,13 +12,16 @@ h4 = t('activerecord.attributes.exercise_collections.exercises')
   table.table
     thead
       tr
+        th = '#'
         th = t('activerecord.attributes.exercise.title')
         th = t('activerecord.attributes.exercise.execution_environment')
         th = t('activerecord.attributes.exercise.user')
         th = t('shared.actions')
     tbody
-      - @exercises.sort_by{|c| c.title}.each do |exercise|
+      - @exercise_collection.items.sort_by{|item| item.position}.each do |exercise_collection_item|
+        - exercise = exercise_collection_item.exercise
         tr
+          td = exercise_collection_item.position
           td = link_to(exercise.title, exercise)
           td = link_to_if(exercise.execution_environment && policy(exercise.execution_environment).show?, exercise.execution_environment, exercise.execution_environment)
           td = exercise.user.name