code: function processAllRelations(callback) {
      var i, modelName, relation, relations, result = [];
      for (modelName in relationships) {
          if (relationships.hasOwnProperty(modelName)) {
              relations = relationships[modelName];
              for (i = 0; i < relations.length; i = i + 1) {
                  relation = relations[i];
                  result.push(callback(modelName, relation.type, relation.model, relation.details));
              }
          }
      }
      return result;
  }
docs: Iterates all relations and executes given callback on them. Callback is passed
  ({string} modelName, {string} relationType, {string} targetModelName, {Object} relationOptions)
  @private
  @param {function} callback - Callback function.
  @returns {Array}