Add scales to framework. Change calculations to first group and then

average those groupings and the way up the framework.  Likert scores for
a survey_item are averaged.  Then all the survey_items in a scale are
averaged.  Then student scales in a measure are averaged.  And teacher
scales in a measure are averaged.  Then the average of those two
calculations becomes the score for a measure.  Then the measures in a
subcategory are averaged.

db/migrate/20220217123648_create_scales.rb

@@ -0,0 +1,10 @@
+class CreateScales < ActiveRecord::Migration[7.0]
+  def change
+    create_table :scales do |t|
+      t.string :scale_id, index: { unique: true }, null: false
+      t.references :measure, null: false, foreign_key: true
+
+      t.timestamps
+    end
+  end
+end

db/migrate/20220217164706_add_scale_to_survey_item.rb

@@ -0,0 +1,6 @@
+class AddScaleToSurveyItem < ActiveRecord::Migration[7.0]
+  def change
+    add_reference :survey_items, :scale, null: false, foreign_key: true
+    remove_reference :survey_items, :measure, null: false, foreign_key: true
+  end
+end

db/migrate/20220217170442_add_scale_to_admin_data_item.rb

@@ -0,0 +1,7 @@
+class AddScaleToAdminDataItem < ActiveRecord::Migration[7.0]
+  def change
+    add_reference :admin_data_items, :scale, null: false, foreign_key: true
+    remove_reference :admin_data_items, :measure
+    add_index :admin_data_items, :admin_data_item_id, unique: true
+  end
+end