Add ci config global and before_script entries

lib/gitlab/ci/config/entry/base_entry.rb

+module Gitlab
+  module Ci
+    class Config
+      module Entry
+        class BaseEntry
+          def initialize(hash, config, parent = nil)
+            @hash = hash
+            @config = config
+            @parent = parent
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/ci/config/entry/before_script.rb

+module Gitlab
+  module Ci
+    class Config
+      module Entry
+        class BeforeScript < BaseEntry
+          def leaf?
+            true
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/ci/config/entry/global.rb

+module Gitlab
+  module Ci
+    class Config
+      module Entry
+        class Global < BaseEntry
+          def allowed_keys
+            []
+          end
+        end
+      end
+    end
+  end
+end

spec/lib/gitlab/ci/config/entry/before_script_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Ci::Config::Entry::BeforeScript do
+  let(:entry) { described_class.new(hash, config) }
+
+  describe '#leaf?' do
+    it 'is a leaf entry' do
+      expect(entry).to be_leaf
+    end
+  end
+end

spec/lib/gitlab/ci/config/entry/global_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Ci::Config::Entry::Global do
+
+end

spec/lib/gitlab/ci/config_spec.rb

@@ -37,7 +37,8 @@ describe Gitlab::Ci::Config do
       describe '.new' do
         it 'raises error' do
           expect { config }.to raise_error(
-            Gitlab::Ci::Config::LoaderError, /Invalid configuration format/
+            Gitlab::Ci::Config::LoaderError,
+            /Invalid configuration format/
           )
         end
       end