def get_version(node, group, oid)
      repo, path = yield_repo_and_path(node, group)
      repo = Rugged::Repository.new repo
      repo.blob_at(oid, path).content
    rescue StandardError
      'version not found'
    end
def get_version(node, group, oid)
      repo, path = yield_repo_and_path(node, group)
      repo = Rugged::Repository.new repo
      repo.blob_at(oid, path).content
    rescue StandardError
      'version not found'
    end
give the blob of a specific revision