@SageAdviceDnD Can I use mending to repair/heal Warforged? If yes, it would be like full heal? If not how can I heal them?
— Raphael F. M. Mariz (@fillipemariz) February 2, 2015
For 5e Warfogerd you could use 3.5edition rule that allow all Cure spells, however, provide only half their normal effect.
Repair spells are a little tricky because Mending Cantrip could be abused (unlimited healing for Warforged!)
So if your Warforge player want take a wizard level just to have unlimited Mending Cantrip is better to use Cure spell at full effect (not halved).
Cantrip can’t be healing spell as described in Dungeon Master Guide p. 284
Another solution could be place Mending as a 1st level spell but you need to tweak it a little.