Added a link to Learn Ruby The Hard Way

It's a really good manual, I'm surprised it's not on the list already.
Add translation for 12-27 Jun 2013 news posts (id)
Merge pull request #205 from id-ruby/id/translate_news/2013_jun

Add translation for 12-27 Jun 2013 news posts (id)
Use unique timestamps
Fix markdown, add some newlines
Translation for 06-27-2013 news posts (es)
Transaltion of the security page (es)

Will include more recent known issues to the list
as they are properly translated and reviewed.
Typo fixes in 06-27-2013 news posts (es)
Fix metadata in news posts, add/remove newlines (es)
Add publication dates on security page (es)
Missing change list on ruby 2.0.0-p247 announcement (es)
add ruby 2.0.0-p247 released news for zh_cn
adds ruby 1.8.7-p374 release news for zh_cn
adds ruby 1.9.3-p448 release news for zh_cn
adds l10n of translated_by for zh_cn
Translated latest security advisory post (pl)
Merge pull request #206 from mlen/master

[pl] Translated latest security advisory
Add news about some new releases (pl)
Typo fixes in news article (pl)
we retire 1.8.7.