Add Instiki to Wikis (#3111)

* Add Ruby License

README.md

@@ -1906,6 +1906,7 @@ _See also: [Wikimatrix](https://www.wikimatrix.org/), [Wiki Engines - WikiIndex]
 - [Dokuwiki](https://www.dokuwiki.org/DokuWiki) - 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. ([Source Code](https://github.com/splitbrain/dokuwiki)) `GPL-2.0` `PHP`
 - [Gitit](https://github.com/jgm/gitit) - 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. `GPL-2.0` `Haskell`
 - [Gollum](https://github.com/gollum/gollum) - Simple, Git-powered wiki with a sweet API and local frontend. `MIT` `Ruby`
+- [Instiki](https://golem.ph.utexas.edu/wiki/instiki/show/HomePage) - Instiki is a wiki clone so pretty and easy to set up, you'll wonder if it’s really a wiki. Runs on Rails and focuses on portability and stability. ([Source Code](https://github.com/parasew/instiki)) `Ruby` `Ruby`
 - [jingo](https://github.com/claudioc/jingo) - Git based wiki engine written for node.js, with a decent design, a search capability and good typography. `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. ([Demo](https://en.wikipedia.org/wiki/Main_Page), [Source Code](https://phabricator.wikimedia.org/diffusion/MW/)) `GPL-2.0` `PHP`
 - [MoinMoin](https://moinmo.in/) - Advanced, easy to use and extensible WikiEngine with a large community of users. ([Source Code](https://github.com/moinwiki/moin-1.9)) `GPL-2.0` `Python`
@@ -1976,6 +1977,7 @@ _See also: [Wikimatrix](https://www.wikimatrix.org/), [Wiki Engines - WikiIndex]
 - `MPL-2.0` - [Mozilla Public License](https://www.mozilla.org/MPL/2.0/index.txt)
 - `OSL-3.0` - [Open Software License 3.0](https://opensource.org/licenses/osl-3.0.php)
 - `Sendmail` - [Sendmail License](https://www.sendmail.com/pdfs/open_source/sendmail_license.pdf)
+- `Ruby` - [Ruby License](http://www.ruby-lang.org/en/LICENSE.txt)
 - `Unlicense` - [The Unlicense](https://unlicense.org/)
 - `WTFPL` - [Do What the Fuck You Want to Public License](http://www.wtfpl.net/about/)
 - `Zlib` - [Zlib/libpng License](https://opensource.org/licenses/Zlib)