Update introduction.md

Added Deadly Skills list.
Update introduction.md

Added additional deadly skill.
Merge pull request #2 from Angelfirenze/new_rules

Too many people are spilling coffee.
Merge pull request #1 from Angelfirenze/deadly_skills

Update introduction.md
Merge branch 'master' of https://github.com/Angelfirenze/dojo_rules

Conflicts:
	introduction.md