Remove Gruik (abandoned)

Fixes #948

README.md

@@ -1134,7 +1134,6 @@ See also [Documentation Generators](#documentation-generators), [Wikimatrix](htt
   * [Dokuwiki](https://www.dokuwiki.org/DokuWiki) - An easy to use, lightweight, standards-compliant wiki engine with a simple syntax allowing reading the data outside the wiki. All data is stored in plain files, therefore no database is required. `GPL` `PHP`
   * [Gitit](https://github.com/jgm/gitit) - A wiki program that stores pages and uploaded files in a git repository, which can then be modified using the VCS command line tools or the wiki's web interface. ([Demo](http://gitit.johnmacfarlane.net/)) `GPLv2` `Haskell`
   * [Gollum](https://github.com/gollum/gollum) - A simple, Git-powered wiki with a sweet API and local frontend. `MIT` `Ruby`
-  * [Gruik](http://gruik.io/) - An open-source markdown note-taking web app. ([Source Code](https://github.com/grena/gruik)) `GPLv3` `PHP`
   * [jingo](https://github.com/claudioc/jingo) - A git based wiki engine written for node.js, with a decent design, a search capability and a good typography. ([Demo](http://jingo.cica.li:6067/wiki/home), [Source Code](https://github.com/claudioc/jingo)) `MIT` `NodeJS`
   * [Mediawiki](https://www.mediawiki.org/wiki/MediaWiki) - MediaWiki is a free and open-source wiki software package written in PHP. It serves as the platform for Wikipedia and the other Wikimedia projects, used by hundreds of millions of people each month. ([Source Code](https://phabricator.wikimedia.org/diffusion/MW/)) `GPLv2` `PHP`
   * [MoinMoin](https://moinmo.in/) - An advanced, easy to use and extensible WikiEngine with a large community of users. ([Source Code](http://hg.moinmo.in/moin)) `GPLv2` `Python`