Adds AddThis social sharing and email buttons

[codecov-io]

Codecov Report

Merging #279 into master will decrease coverage by 0.62%. The diff coverage is 84.61%.

@@            Coverage Diff             @@
##           master     #279      +/-   ##
==========================================
- Coverage   61.77%   61.15%   -0.63%     
==========================================
  Files          16       17       +1     
  Lines         259      278      +19     
  Branches       54       54              
==========================================
+ Hits          160      170      +10     
- Misses         99      108       +9

Impacted Files	Coverage Δ
app/App.tsx	0% <0%> (ø)	:arrow_up:
app/cards/Card.tsx	95% <100%> (+0.26%)	:arrow_up:
app/components/AddThis.tsx	100% <100%> (ø)

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[jvoros]

It doesn't look like much in the end. But it took a lot of work to get there. Adding to the window event listener instead of react lifecycle hooks was the big fix.

[dsifford]

@jvoros I just tried actually running this now for the first time and it doesn't work for me.... Does it work for you?

[dsifford]

@jvoros Status on this?

[dsifford]

Can we close this?