progress(modules + hashmaps): finished modules and almost done hashmaps

exercises/10_modules/modules3.rs

@@ -4,6 +4,8 @@
 // TODO: Bring `SystemTime` and `UNIX_EPOCH` from the `std::time` module into
 // your scope. Bonus style points if you can do it with one line!
 // use ???;
+use std::time::SystemTime;
+use std::time::UNIX_EPOCH;
 
 fn main() {
     match SystemTime::now().duration_since(UNIX_EPOCH) {