Gild says "Exile target creature. Put a colorless artifact token named Gold onto the battlefield. It has "Sacrifice this artifact: Add one mana of any color to your mana pool."". I assume that that means that the token goes into play under your control (assuming you were the one who cast Gild) and not the person who's creature you exiled?
Yes, the token comes into play under the control of the player who played Gild. This is specified by rule 110.2a:
Gild's effect instructs you (the player who controls the spell) to put the token into play, so it comes into play under your control.
A ruling on the Gatherer page states this explicitly:
It enters the battlefield under the control of Gild's controller.
That's Gild's controller when it resolved.
By default, that's the player who cast Gild.
By default, that's the player who owns Gild.
So by default, it'll come under control of the player who owns Gild, but as you can see, there are some variables.