Add a new intentionally vulnerable Rust web application

## Motivation

SecDevLab's goal is to provide examples of how security vulnerabilities could be fixed, but we don't currently have any examples using the [Rust](https://www.rust-lang.org/) language.

## It would be great if

We had any Rust app illustrating any [OWASP Top 10](https://owasp.org/www-project-top-ten/) vulnerability and how it could be exploited by an attacker.

## What we expect

The new app must have a complete `README.md` with all the steps on how to get the environment ready to run it, how it can be installed, and how an attacker could compromise it.

The app should be similar to the existing web apps, such as [this one](https://github.com/globocom/secDevLabs/tree/master/owasp-top10-2017-apps/a7/gossip-world).

## Tips

* [README Template](https://github.com/globocom/secDevLabs/blob/master/docs/README_Template.md)
* [Makefile Template](https://github.com/globocom/secDevLabs/blob/master/docs/Makefile)
* [Init script Template](https://github.com/globocom/secDevLabs/blob/master/docs/check-init.sh)

## Note
We may open any issues such as this one if more than one DEV is interested in building Rust applications. Let's build with Rust all [OWASP Top 10 vulnerabilities](https://github.com/globocom/secDevLabs)! 🚀