Add 2.0.0 to travis.yml and ignore ruby-head, rbx-19mode failures
Add 2.0.0 to travis.yml and ignore ruby-head, rbx-19mode failures

airbnb/poseidon,chingor13/poseidon,gjackson12/poseidon,apptentive-engineering/poseidon,Tapjoy/poseidon,SponsorPay/poseidon,nepalez/poseidon,Shopify/poseidon,bpot/poseidon,codeclimate/poseidon,ListenFirstMedia/poseidon