Added a main() to Strategy pattern.
Added a main() to Strategy pattern.

jdavis/rust-design-patterns,ianlet/rust-design-patterns,beni55/rust-design-patterns,beni55/rust-design-patterns,beni55/rust-design-patterns,jdavis/rust-design-patterns,ianlet/rust-design-patterns,jdavis/rust-design-patterns,ianlet/rust-design-patterns,jdavis/rust-design-patterns