Fix Rubocop offense

app/controllers/exercises_controller.rb

@@ -176,7 +176,7 @@ class ExercisesController < ApplicationController
     ActiveRecord::Base.transaction do
       exercise = ::ProformaService::Import.call(zip: tempfile, user: user)
       exercise.save!
-      return render json: {}, status: :created
+      render json: {}, status: :created
     end
   rescue Proforma::ExerciseNotOwned
     render json: {}, status: :unauthorized

db/seeds.rb

@@ -23,7 +23,7 @@ Rails.application.eager_load!
 (ApplicationRecord.descendants - [ActiveRecord::SchemaMigration, User]).each(&:delete_all)
 
 # delete file uploads
-FileUtils.rm_rf(Rails.root.join('public/uploads'))
+FileUtils.rm_rf(Rails.public_path.join('uploads'))
 
 # load environment-dependent seeds
 load(Rails.root.join("db/seeds/#{Rails.env}.rb"))

spec/uploaders/file_uploader_spec.rb

@@ -11,7 +11,7 @@ describe FileUploader do
   after { uploader.remove! }
 
   it 'uses the specified storage directory' do
-    expect(uploader.file.path).to start_with(Rails.root.join('public', uploader.store_dir).to_s)
+    expect(uploader.file.path).to start_with(Rails.public_path.join(uploader.store_dir).to_s)
     expect(uploader.file.path).to end_with(file_path.basename.to_s)
   end