sort sql injection vulnerability, add gem brakeman

Gemfile

@@ -74,6 +74,7 @@ group :development, :test do
  gem 'faker', '~> 2.6.0'
  gem 'pry-rails', '~> 0.3.9'
  gem 'action-cable-testing'
+ gem 'brakeman'
 end
 
 group :development do

Gemfile.lock

@@ -76,6 +76,7 @@ GEM
  bootstrap-sass (3.4.1)
  autoprefixer-rails (>= 5.2.1)
  sassc (>= 2.0.0)
+ brakeman (4.7.2)
  builder (3.2.3)
  byebug (11.0.1)
  capybara (3.29.0)
@@ -351,6 +352,7 @@ DEPENDENCIES
  aws-sdk-s3 (~> 1)
  bootsnap (~> 1.4.5)
  bootstrap-sass
+ brakeman
  byebug (~> 11.0.1)
  capybara
  codecov

app/controllers/users_controller.rb

@@ -13,7 +13,7 @@ def index
  @users = User.joins(:maps)
  .select('users.*, count(users.id) as maps_count')
  .group('maps.user_id')
- .order(sort_column + ' ' + sort_direction)
+ .order(sort_column => sort_direction)
  .paginate(page: params[:page], per_page: 24)
  render 'users/index'
  end