MSVC builds of Rust on Windows automatically generate `*.pdb` files, which
store debugging information. For more information, see:

* https://github.com/rust-lang/rustlings/issues/275
* https://locka99.gitbooks.io/a-guide-to-porting-c-to-rust/content/debugging_rust/#microsoft-visual-studio

The problem here was two fold:
1. the folder "/target/" would be top-level of the repo only, it should be "target/" to properly exclude target folders anywhere in the repo
2. the default Rust/Cargo folder when compiling code is "debug/", which gets used perhaps more often that "target/", added that

no need to specifically ignore compiled files and executables
as it will be under the target directory

See the [official recommendation](http://doc.crates.io/guide.html#cargotoml-vs-cargolock) 

> * If you're building a library, put Cargo.lock in your .gitignore.
> * If you're building an executable, check Cargo.lock into git.