message: Fix code linting errors
diff: @@ -75,8 +75,8 @@ exports.observeMetrics = function observeMetrics () {
  const challengeKeys = Object.keys(challenges)
  challengeTotalMetrics.set({ count: challengeKeys.length }, 0)
  for (let difficulty = 1; difficulty <= 6; difficulty++) {
  - let count = challengeKeys.filter((key) => (challenges[key].difficulty === difficulty)).length
  - let solved = challengeKeys.filter((key) => (challenges[key].difficulty === difficulty && challenges[key].solved)).length
  + const count = challengeKeys.filter((key) => (challenges[key].difficulty === difficulty)).length
  + const solved = challengeKeys.filter((key) => (challenges[key].difficulty === difficulty && challenges[key].solved)).length
  challengeMetrics.set({ difficulty, count }, solved)
  if (solved > 0) challengeTotalMetrics.inc({ count: challengeKeys.length }, solved)
  }
  