rename factory_girl_(rails) to factory_bot_(rails)

spec/factories/user_exercise_feedback.rb

@@ -1,7 +1,7 @@
-FactoryGirl.define do
+FactoryBot.define do
   factory :user_exercise_feedback, class: UserExerciseFeedback do
     created_by_external_user
     feedback_text 'Most suitable exercise ever'
   end
 
-end
+end