Add nokogiri to main group
Add nokogiri to main group

As we're using nokogiri as the XmlMini backend as of bd6e94fc7c9c1790622ba29655f6e7e27044dd64,
it should be in the default gem group.

4bic/alaveteli,Br3nda/alaveteli,4bic/alaveteli,andreicristianpetcu/alaveteli_old,nzherald/alaveteli,4bic/alaveteli,nzherald/alaveteli,4bic/alaveteli,nzherald/alaveteli,nzherald/alaveteli,Br3nda/alaveteli,andreicristianpetcu/alaveteli_old,nzherald/alaveteli,Br3nda/alaveteli,andreicristianpetcu/alaveteli_old,Br3nda/alaveteli,andreicristianpetcu/alaveteli,andreicristianpetcu/alaveteli_old,andreicristianpetcu/alaveteli,4bic/alaveteli,andreicristianpetcu/alaveteli,andreicristianpetcu/alaveteli_old,Br3nda/alaveteli,andreicristianpetcu/alaveteli,andreicristianpetcu/alaveteli