feat(response): Add support for rel_uuids

[silasjoisten]

refs #61

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.94%. Comparing base (006cdab) to head (4f4b330).

Additional details and impacted files

@@             Coverage Diff              @@
##             master      #67      +/-   ##
============================================
+ Coverage     93.88%   93.94%   +0.05%     
- Complexity      461      466       +5     
============================================
  Files            72       72              
  Lines          1620     1636      +16     
============================================
+ Hits           1521     1537      +16     
  Misses           99       99              

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[frastel]

LGTM for the case the app won't break when rel_uuids do exist in the response. Any further discussion in #67 .

[edodusi]

rel_uuids should also be added to the StoryResponse because it can optionally be part the the single story response as well, not only the multiple stories response