Add: Stone Game

[awesee]

No description provided.

[codecov]

Codecov Report

Merging #701 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #701      +/-   ##
==========================================
+ Coverage   99.28%   99.28%   +<.01%     
==========================================
  Files         219      220       +1     
  Lines        2234     2236       +2     
==========================================
+ Hits         2218     2220       +2     
  Misses         16       16

Impacted Files	Coverage Δ
problems/stone-game/stone_game.go	100% <100%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 9b3a5ec...15fa572. Read the comment docs.