Merge pull request #951 from saveriomiroddi/sav/add_demonstrate_testing_framework

Add `demonstrate` testing framework

README.md

@@ -641,6 +641,7 @@ See also [Are we (I)DE yet?](https://areweideyet.com/) and [Rust Tools](https://
 
 [[testing](https://crates.io/keywords/testing)]
 
+* [demonstrate](https://crates.io/crates/demonstrate) — Declarative Testing Framework [![Build Status](https://github.com/austinsheep/demonstrate/workflows/Continuous%20Integration/badge.svg?branch=master)](https://github.com/austinsheep/demonstrate)
 * [mockiato](https://crates.io/crates/mockiato) — A strict, yet friendly mocking library for Rust 2018 [<img src="https://api.travis-ci.com/mockiato/mockiato.svg?branch=master">](https://travis-ci.com/mockiato/mockiato)
 * [mutagen](https://crates.io/crates/mutagen) — A source-level mutation testing framework (nightly only) [<img src="https://api.travis-ci.org/llogiq/mutagen.svg?branch=master">](https://travis-ci.org/llogiq/mutagen)
 * [AlKass/polish](https://github.com/AlKass/polish) — Mini Testing/Test-Driven Framework [![Build Status](https://api.travis-ci.org/AlKass/polish.svg?branch=master)](https://travis-ci.org/AlKass/polish) [![Crates Package Status](https://img.shields.io/crates/v/polish.svg)](https://crates.io/crates/polish)