Add JRuby deps to gemspec.
Add JRuby deps to gemspec.

rafal-radziszewski/rpush,mandarin6b0/rpush,joshuairl/rpush,zenjoy/rpush,ileitch/rapns,krakatoa/rpush,kjnsn/rpush,chiu/rpush,jmnsf/rpush,amaierhofer/rpush,rpush/rpush,aried3r/rpush,rafal-radziszewski/rpush,eleostech/rapns,zakwanhaj/rpush