upgrade rails to 4.1.8

to address [CVE-2014-7829](https://groups.google.com/forum/#!topic/rubyonrails-security/rMTQy4oRCGk)
Merge pull request #40 from bitzesty/upgrade-rails

upgrade rails to 4.1.8
button colours, WIP
button colours
Merge pull request #41 from bitzesty/button-colours-rebased

Button colours
heading texts for synonyms related pages
Merge pull request #42 from bitzesty/headings-text

heading texts for synonyms related pages
Adding a CHANGELOG from the last release