update ruby versions used on travis tests
update ruby versions used on travis tests

jnicklas/capybara,jnicklas/capybara,olivierlacan/capybara,teamcapybara/capybara,olivierlacan/capybara,teamcapybara/capybara,olivierlacan/capybara,twalpole/capybara,twalpole/capybara,jnicklas/capybara,teamcapybara/capybara,twalpole/capybara