Shrimp Sausage Gumbo

Name: Shrimp & Sausage Gumbo
Ingredients: 4 tbsp. unsalted butter; 0.25 c. all-purpose flour; 1 small yellow onion, chopped; 1 medium green bell pepper, seeds and ribs removed, chopped; 2 stalks celery, finely sliced; 12 oz. andouille sausage, sliced into 1/2 rounds; 2 cloves garlic, finely chopped; 1 tbsp. Cajun seasoning (without salt); 4 c. low-sodium chicken broth; 1 (15-oz.) can fire-roasted diced tomatoes; 1 bay leaf; 1 lb. medium shrimp, peeled, deveined; 3 scallions, sliced