The Internet Encyclopedia of Philosophy defines it slightly differently: "Divine Command Theory is the view that morality is somehow dependent upon God, and that moral obligation consists in obedience to God’s commands."
Martin Luther said in On the Bondage of the Will:
God is that Being, for whose will no cause or reason is to be
assigned, as a rule or standard by which it acts; seeing that, nothing
is superior or equal to it, but it is itself the rule of all things.
For if it acted by any rule or standard, or from any cause or reason,
it would be no longer the will of GOD. Wherefore, what God wills, is
not therefore right, because He ought or ever was bound so to will;
but on the contrary, what takes place is therefore right, because He
John Calvin, usually considered the father of reformed theology, said much the same in Institutes of the Christian Religion (3.23.2):
For God’s will is so much the highest rule of righteousness that
whatever he wills, by the very fact that he wills it, must be
considered righteous. When, therefore, one asks why God has so done,
we must reply: because he has willed it. But if you proceed further to
ask why he so willed, you are seeking something greater and higher
than God’s will, which cannot be found.
The Westminster Confession of Faith, the classic statement of reformed theology, says in chapter 2:
God has all life, glory, goodness, blessedness, in and of Himself; and
is alone in and unto Himself all-sufficient.
In chapter 16 it says:
Good works are only such as God has commanded in His holy Word.
So it seems clear that reformed theology supports divine command theory. However, your understanding of it is not one shared by reformed theology. Things are good because God commands them, but he commands them because they accord with his character. "God has all ... goodness... in and of Himself," after all.