Update CONTRIBUTING.md

added code templates to contributing
fixed treasure chest weapon bug
fixed blackjack init selection bug
Merge pull request #971 from NimbusBP1729/blackjack_bug

fixed blackjack init selection bug
Merge pull request #969 from NimbusBP1729/weapon_bug_fix

fixed treasure chest weapon bug
Merge pull request #968 from NimbusBP1729/editcontributing

Update CONTRIBUTING.md
Add and sort missed contributors