Code review on a multithreaded server

Good evening guys, I am new to rust and have been trying my best to adapt to the language, though i come from a Golang background. So, in the course of learning the language, I built this little project, to understand how backend servers are built with rust. Please I need a review on the code, so that i can know how to improve and program better in rust. Here is the link to the repo: [GitHub - dositadi/librer-a: This is a book store api built with rust to gain a better grasp of the rust ecosys...