moves API logic inside its own module

src/main.rs

@@ -2,9 +2,10 @@ extern crate actix_web;
 extern crate dotenv;
 extern crate env_logger;
 extern crate lootalot_db;
-extern crate serde;
+#[macro_use] extern crate serde;
 
 mod server;
+mod api;
 
 fn main() {
     std::env::set_var("RUST_LOG", "actix_web=info");