[gitg/wip/submodules] Added Stage.stage_commit

[Jesse van den Kieboom <jessevdk src gnome org>]

commit 5f207a31277d53810305def7fe9b29f54425cc35
Author: Jesse van den Kieboom <jessevdk gmail com>
Date:   Sun Dec 14 12:05:54 2014 +0100

    Added Stage.stage_commit

 libgitg/gitg-stage.vala |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)
---
diff --git a/libgitg/gitg-stage.vala b/libgitg/gitg-stage.vala
index 687d879..a0af236 100644
--- a/libgitg/gitg-stage.vala
+++ b/libgitg/gitg-stage.vala
@@ -701,6 +701,26 @@ public class Stage : Object
                yield stage(d_repository.get_workdir().resolve_relative_path(path));
        }
 
+       /**
+        * Stage a commit to the index.
+        *
+        * @param path path relative to the working directory.
+        * @param id the id of the commit object to stage at the given path.
+        *
+        * Stage a commit to the index with a relative path. This will record the
+        * given commit id for file pointed to at path in the index.
+        */
+       public async void stage_commit(string path, Ggit.Commit commit) throws Error
+       {
+               yield thread_index((index) => {
+                       var entry = d_repository.create_index_entry_for_path(path, commit.get_id());
+                       entry.set_commit(commit);
+
+                       index.add(entry);
+                       index.write();
+               });
+       }
+
        private void copy_stream(OutputStream dest, InputStream src, ref size_t pos, size_t index, size_t 
length) throws Error
        {
                if (length == 0)