Validate Links

Hello, I wrote a tool that can validate README links. It can be run when someone submits a pull request or pushes a commit.

For example, you would see that

```
https://github.com/mohebifar/lebab redirects to
https://github.com/lebab/lebab

https://github.com/facebook/jstransform redirects to
https://github.com/facebookarchive/jstransform

https://github.com/joshheyse/typescript-brunch is now 404
```

..and more: see https://gist.github.com/52dc0760ab5a31a68503aebe70b7ad79

This tool is currently being used by
- https://github.com/matteocrippa/awesome-swift
- https://github.com/brabadu/awesome-fonts
- and many [more](https://github.com/dkhamsing/awesome_bot/blob/master/status/status.md)

Examples
- https://travis-ci.org/matteocrippa/awesome-swift/builds/96526196 ok ✅
- https://travis-ci.org/matteocrippa/awesome-swift/builds/96722421 link redirected / rename 🔴
- https://travis-ci.org/dkhamsing/open-source-ios-apps/builds/96763135 bad link / project deleted 🔴
- https://travis-ci.org/dkhamsing/open-source-ios-apps/builds/95754715 dupe 🔴

If you are interested, connect this repo to https://travis-ci.org/ and add a [`.travis.yml`](https://github.com/dkhamsing/open-source-ios-apps/blob/master/.travis.yml) file to the project (you can also use Circle CI or other CI services).

See https://github.com/dkhamsing/awesome_bot for options, more information
Feel free to leave a comment :smile: