# File lib/versionomy/format.rb, line 115
      def add_directory(path_, high_priority_=false)
        path_ = ::File.expand_path(path_)
        @mutex.synchronize do
          unless @directories.include?(path_)
            if high_priority_
              @directories.unshift(path_)
            else
              @directories.push(path_)
            end
          end
        end
      end