I don't know all tables and DBCs used here, but for sure you will have to create a new skill (like Arms, Fury, Protection are). That means editing:
SkillLine.dbc - to create skill
SkillRaceClassInfo.dbc - to make skill learnable/usable by selected classes and races
SkillLineAbility.dbc - to assign spells to that skill (in this case it will make them appear in correct section in spellbook)
And probably something more, dunno what. Check blizzlike class skills, like for instance mentioned warrior's Arms skill.