code: function(hash, nestingLevel) {
      // reduce nestingLevel to hash size
      nestingLevel = Math.min(hash.length - 1, nestingLevel);
  
      if (nestingLevel === 0) {
          return hash;
      }
  
      var hashArr = hash.split('');
      for (var i = 0; i < nestingLevel; i++) {
          hashArr.splice(i * 2 + 1, 0, '/');
      }
  
      return hashArr.join('');
  }
docs: Returns nesting path.
  @example
  getFreezeNestingPath('abc', 1) -> a/bc
  getFreezeNestingPath('abc', 2) -> a/b/c
  getFreezeNestingPath('abc', 5) -> a/b/c
  
  @param {String} hash Freezed filename.
  @param {Number} nestingLevel
  @returns {String}