Make gistub work with JRuby

Hello! First of all, thanks for putting together this great project.

I was trying to deploy gistub using JRuby, but it wasn't possible, due Redcarpet using native C libraries.

I have a branch where I'm using a pure ruby implementation instead - Kramdown. Would you be interested in this patch? In this branch, both JRuby and Ruby 2.0.0 are also supported.

Thank you for your pull request. Basically I'm not a JRuby user. So I didn't check for JRuby when adding markdown support. Sorry for that.

I've tried your patch and found that Kramdown fails to parse markdown in some cases. Tentatively I added begin-rescue but there might be a better fix.

gistub/app/helpers/application_helper.rb

Lines 43 to 47 in bb2e165

    
           begin 
        
             Kramdown::Document.new(md_body).to_html 
        
           rescue Exception 
        
             md_body 
        
           end

Thanks!

found that Kramdown fails to parse markdown in some cases.

In detail, the following error occurrs on JRuby.

Java::JavaLang::ArrayIndexOutOfBoundsException in Gists#show

On CRuby, everything seems to be fine.

Thanks for merging in so fast!

I was investigating the bug and it seems to be related to this thread: http://jira.codehaus.org/browse/JRUBY-6613

I've tested the given scenario and everything worked fine on Jruby 1.7.3.

Anyway, thank you for the great support to the project! 👍

Thank you for your investigation! Indeed my JRuby environment is too old (1.6.x).

	begin
	Kramdown::Document.new(md_body).to_html
	rescue Exception
	md_body
	end