Showing an example of Vectors

vectors.rs

fn main() {
    let mut my_vec: Vec<i32> = Vec::new(); // my_vec = []
    my_vec.push(7); // my_vec = [7]
    my_vec.push(8); // my_vec = [7, 8]
    my_vec.push(7); // my_vec = [7, 8, 7]
}