Garlic and Asparagus Pasta with Lemon Cream

8 oz. dried rotini pasta
1 tablespoon butter/margarine
2 cups yellow summer squash
2 cloves garlic, minced
2 cups water
2 tablespoons lemon zest
1/2 cup ragu white sauce

Cook pasta. Combine water, lemon zest, and ragu sauce in saucepan. Whisk until smooth, bring to a slow boil and simmer for 5 minutes. Melt butter in skillet; add asparagus, squash, garlic and saute until vegetables are soft. Combine pasta and veggies and toss. Pour hot lemon sauce on top and gently stir. Salt and pepper to taste.