Add submodules info for repository via grit

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    gitlab_git (5.1.0)
+    gitlab_git (5.2.0)
       activesupport (~> 4.0.0)
       charlock_holmes (~> 0.6.9)
       gitlab-grit (~> 2.6.1)
@@ -33,7 +33,7 @@ GEM
     escape_utils (0.2.4)
     ffi (1.8.1)
     formatador (0.2.4)
-    gitlab-grit (2.6.3)
+    gitlab-grit (2.6.4)
       charlock_holmes (~> 0.6.9)
       diff-lcs (~> 1.1)
       mime-types (~> 1.15)

lib/gitlab_git/repository.rb

@@ -320,6 +320,24 @@ def refs_hash
       def lookup(oid)
         rugged.lookup(oid)
       end
+
+      # Return hash with submodules info for this repository
+      #
+      # Ex.
+      #   {
+      #     "rack"  => {
+      #       "id" => "c67be4624545b4263184c4a0e8f887efd0a66320",
+      #       "path" => "rack",
+      #       "url" => "git://github.com/chneukirchen/rack.git"
+      #     },
+      #     "encoding" => {
+      #       "id" => ....
+      #     }
+      #   }
+      #
+      def submodules(ref)
+        Grit::Submodule.config(grit, ref)
+      end
     end
   end
 end

spec/repository_spec.rb

@@ -153,4 +153,26 @@
       its(:data) { should include "bundle exec rake db:seed_fu RAILS_ENV=test" }
     end
   end
+
+  context :submodules do
+    let(:repository) { Gitlab::Git::Repository.new(TEST_SUB_REPO_PATH) }
+    let(:submodules) { repository.submodules('898ce92b0e0b5ade8a7ef7e3c779dda476b3eef8') }
+
+    it { submodules.should be_kind_of Hash }
+    it { submodules.empty?.should be_false }
+
+    describe :submodule do
+      let(:submodule) { submodules.first }
+
+      it 'should have valid data' do
+        submodule.should == [
+          "rack", {
+            "id"=>"c67be4624545b4263184c4a0e8f887efd0a66320",
+            "path"=>"rack",
+            "url"=>"git://github.com/chneukirchen/rack.git"
+          }
+        ]
+      end
+    end
+  end
 end