Apply automatic rubocop fixes

app/models/intervention.rb

@@ -1,5 +1,6 @@
-class Intervention < ApplicationRecord
+# frozen_string_literal: true
 
+class Intervention < ApplicationRecord
   has_many :user_exercise_interventions
   has_many :users, through: :user_exercise_interventions, source_type: 'ExternalUser'
 
@@ -8,9 +9,8 @@ class Intervention < ApplicationRecord
   end
 
   def self.createDefaultInterventions
-    %w(BreakIntervention QuestionIntervention).each do |name|
+    %w[BreakIntervention QuestionIntervention].each do |name|
       Intervention.find_or_create_by(name: name)
     end
   end
-
-end
+end