code: function enumerateFunctions(relations) {
      const blacklist = [
          'use',
          'tearDown',
          'define'
      ];
      return _.reduce(relations, function(functions, prop, key) {
          if (blacklist.indexOf(key) === -1 && _.isFunction(prop)) {
              functions.push(key);
          }
  
          return functions;
      }, []);
  }
docs: loop through enumerable properties of obj
  and store the keys of properties which are functions
  and are not in the blacklist
  @param {object} relations
  @return {array} an array of keys