Issue #18  Botao do twitter adicionado.

 Mudanças a serem submetidas:
	modificado: app/helpers/jobs_helper.rb
	modificado: app/views/jobs/show.html.erb
	modificado: app/views/layouts/application.html.erb
Merge pull request #34 from jhonylucas74/iss18

Issue #18  Botao do twitter adicionado.