Martha's Spanish Rice and Sausage

INGREDIENTS

• 1/4 cup vegetable oil
• 1 small onion, diced
• 1 tablespoon minced garlic
• 1 pound smoked sausage, cut into bite-sized pieces
• 1 1/2 cups uncooked white rice
• 2 cups water
• 3/4 (8 ounce) can tomato sauce, or to taste
• 1 teaspoon adobo seasoning
• salt and ground black pepper to taste