Add section attribute to Entry

Extending this class to support a "section" attribute will allow us
to eventually support CODEOWNERS files that offer organizing entries
into different sections.

ee/lib/gitlab/code_owners/entry.rb

@@ -5,15 +5,15 @@ module Gitlab
     class Entry
       include ::Gitlab::Utils::StrongMemoize
 
-      Data = Struct.new(:pattern, :owner_line)
+      Data = Struct.new(:pattern, :owner_line, :section)
 
       attr_reader :data
       protected :data
 
-      delegate :pattern, :hash, :owner_line, to: :data
+      delegate :pattern, :hash, :owner_line, :section, to: :data
 
-      def initialize(pattern, owner_line)
-        @data = Data.new(pattern, owner_line)
+      def initialize(pattern, owner_line, section = "CODEOWNERS")
+        @data = Data.new(pattern, owner_line, section)
       end
 
       def all_users

ee/spec/lib/gitlab/code_owners/entry_spec.rb

@@ -2,7 +2,13 @@
 require 'spec_helper'
 
 describe Gitlab::CodeOwners::Entry do
-  subject(:entry) { described_class.new('/**/file', '@user jane@gitlab.org @group @group/nested-group') }
+  subject(:entry) do
+    described_class.new(
+      "/**/file",
+      "@user jane@gitlab.org @group @group/nested-group",
+      "Documentation"
+    )
+  end
 
   let(:user) { build(:user, username: 'user') }
   let(:group_user) { create(:user) }
@@ -13,7 +19,7 @@ describe Gitlab::CodeOwners::Entry do
   end
 
   it 'is uniq by the pattern and owner line' do
-    equal_entry = described_class.new('/**/file', '@user jane@gitlab.org @group @group/nested-group')
+    equal_entry = entry.clone
     other_entry = described_class.new('/**/other_file', '@user jane@gitlab.org @group')
 
     expect(equal_entry).to eq(entry)