Add frozen string literal magic comment

This is enabled by default in later versions of Rubocop. Making this
change now removes this conflict for people running later versions.

Automatically fixed with `rubocop -a`

.rubocop.yml

@@ -54,6 +54,9 @@ Style/AndOr:
 Style/Not:
   Enabled: false
 
+Style/FrozenStringLiteralComment:
+  Enabled: true
+
 Documentation:
   Enabled: false # TODO: Enable again once we have more docs
 

Gemfile

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source "https://rubygems.org"
 
 ruby RUBY_VERSION

Rakefile

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rubygems"
 require "bundler/gem_tasks"
 require "rspec/core/rake_task"

lib/pundit/policy_finder.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Pundit
   # Finds policy and scope classes for given object.
   # @api public

lib/pundit/rspec.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/array/conversions"
 
 module Pundit

pundit.gemspec

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 lib = File.expand_path("lib", __dir__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require "pundit/version"

spec/policies/post_policy_spec.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "spec_helper"
 
 describe PostPolicy do

spec/policy_finder_spec.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "spec_helper"
 
 describe Pundit::PolicyFinder do

spec/pundit_spec.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "spec_helper"
 
 describe Pundit do

spec/spec_helper.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "pundit"
 require "pundit/rspec"