When the reflexive genitive/dative pronoun (îmi, îți, își, vă, ne) is used with a verb that requires an accusative object, it implies the object is owned by the subject.
I simpler terms, "îți" in the sentence above means the job is owned by the person you're talking to. You could also say "Așa tu faci slujba ta?", but that seems less natural.
You could also use this in other sentences like "îmi spăl mașina" (i'm washing my car) or "și-a pierdut cheile" (he/she lost his/her keys).
I hope that makes sense