Auto-merge: implemented lock file

lib/gitlab_merge.rb

@@ -28,6 +28,9 @@ class GitlabMerge
   end
 
   def pull
+    File.open(File.join(Rails.root, "tmp", "merge_repo", "#{project.path}.lock"), "w+") do |f|
+      f.flock(File::LOCK_EX)
+      
       self.project.repo.git.clone({:branch => merge_request.target_branch}, project.url_to_repo, merge_path)
       #TODO When user do not have permissions then raise exception
       Dir.chdir(merge_path) do
@@ -37,5 +40,7 @@ class GitlabMerge
         output = merge_repo.git.pull({}, "--no-ff", "origin", merge_request.source_branch)
         yield(merge_repo, output)
       end
+
+    end
   end
 end