code: function fetchStargazers(fullName, nextPageUrl) {
    return {
      fullName,
      [CALL_API]: {
        types: [STARGAZERS_REQUEST, STARGAZERS_SUCCESS, STARGAZERS_FAILURE],
        endpoint: nextPageUrl,
        schema: Schemas.USER_ARRAY
      }
    };
  }
docs: Fetches a page of stargazers for a particular repo.
  Relies on the custom API middleware defined in ../middleware/api.js.