Add hostname to Vm

[sasoc]

This migration adds attribute hostname to Vm. For example
virtual machine in Vmware provider has attribute computer name
and now we will be able to render it into hostname.

[sasoc]

cc @miha-plesko

[miq-bot]

Checked commit sasoc@a50c34c with ruby 2.3.3, rubocop 0.52.0, haml-lint 0.20.0, and yamllint 1.10.0
1 file checked, 0 offenses detected
Everything looks fine. 🏆

[miha-plesko]

Thanks @sasoc. @agrare this is the first PR to introduce hostname on VM model, as discussed yesterday on gitter. It appears the db/schema.yml file has been removed, therefore we only had to update the db/schema.rb - or did we miss something?

I kindly ask for a review.

@miq-bot assign @agrare
@miq-bot add_label enhancement

/cc @Ladas

[Ladas]

@miha-plesko you have to send the PR in https://github.com/ManageIQ/manageiq-schema

[sasoc]

@miha-plesko @Ladas I've made new PR(ManageIQ/manageiq-schema#168) in manageiq-schema and I'm closing this one.