Add dependency for image optimizer to the Dockerfile
Add dependency for image optimizer to the Dockerfile

nickjj/build-a-saas-app-with-flask,z123/build-a-saas-app-with-flask,nickjj/build-a-saas-app-with-flask,z123/build-a-saas-app-with-flask,z123/build-a-saas-app-with-flask,nickjj/build-a-saas-app-with-flask,nickjj/build-a-saas-app-with-flask