Leptus implementation.
Modified leptus dep until PR is merged.
Added url qs param since leptus is not able to ignore slashes in uri.
POST / takes the url from the body's application/x-www-form-urlencoded content.
Modified POST from / to /shorten.
Merge pull request #3 from unbalancedparentheses/jfacorro.leptus

Leptus implementation.