Changed merge so that you don't have to pass null in for options

Author: John Haley

example/merge.js

@@ -91,7 +91,7 @@ fse.remove(path.resolve(__dirname, repoDir))
 
 // Merge the two commits
 .then(function() {
-  return nodegit.Merge.commits(repository, ourCommit, theirCommit, null);
+  return nodegit.Merge.commits(repository, ourCommit, theirCommit);
 })
 
 // Merging returns an index that isn't backed by the repository. You have to write it to the repository,

lib/merge.js

@@ -0,0 +1,22 @@
+var NodeGit = require("../");
+var normalizeOptions = require("./util/normalize_options");
+
+var Merge = NodeGit.Merge;
+var mergeCommits = Merge.commits;
+
+/**
+ * Merge 2 commits together and create an new index that can
+ * be used to create a merge commit.
+ *
+ * @param repo Repository that contains the given commits
+ * @param ourCommit The commit that reflects the destination tree
+ * @oaram theirCommit The commit to merge into ourCommit
+ * @param options The merge tree options (null for default)
+ */
+Merge.commits = function(repo, ourCommit, theirCommit, options) {
+  options = normalizeOptions(options, NodeGit.MergeOptions);
+
+  return mergeCommits.call(this, repo, ourCommit, theirCommit, options);
+};
+
+module.exports = Merge;

lib/nodegit.js

@@ -50,6 +50,7 @@ require("./checkout");
 require("./commit");
 require("./diff");
 require("./index");
+require("./merge");
 require("./object");
 require("./odb");
 require("./odb_object");