def detect_format
      formats = Dir.glob("#{@project_root}/output/**/*").map { |path| path }.
                  reject { |s| s =~ %r{/params/} }. # reject output/params folder
                  map { |path| File.extname(path) }.
                  reject { |s| s.empty? }. # reject ""
                  uniq
      if formats.size > 1
        puts "ERROR: Detected multiple formats: #{formats.join(", ")}".colorize(:red)
        puts "All the output files must use the same format.  Either all json or all yml."
        exit 1
      else
        formats.first.sub(/^\./,'')
      end
    end
def detect_format
      formats = Dir.glob("#{@project_root}/output/**/*").map { |path| path }.
                  reject { |s| s =~ %r{/params/} }. # reject output/params folder
                  map { |path| File.extname(path) }.
                  reject { |s| s.empty? }. # reject ""
                  uniq
      if formats.size > 1
        puts "ERROR: Detected multiple formats: #{formats.join(", ")}".colorize(:red)
        puts "All the output files must use the same format.  Either all json or all yml."
        exit 1
      else
        formats.first.sub(/^\./,'')
      end
    end
Returns String with value of "yml" or "json".