[50505921] fix bug hiring manager cannot assign candidates batchly

Signed-off-by: Henry Chen <hchen@vmware.com>
Merge branch 'master' of https://github.com/vmw-tmpst/heroapp-LetsHire into candidate
[50580719] support creating a candidate without adding it to a job opening

Signed-off-by: Henry Chen <hchen@vmware.com>
[50580719] support creating a candidate without adding it to a job opening

1 increase usability by only show 'please select' when necessary.
2 hiring manager couldn't create opening for other department.

Signed-off-by: Henry Chen <hchen@vmware.com>
more code refine for previous fix

Signed-off-by: Henry Chen <hchen@vmware.com>
Merge branch 'master' of https://github.com/vmw-tmpst/heroapp-LetsHire into candidate

Signed-off-by: Henry Chen <hchen@vmware.com>

Conflicts:
	app/views/candidates/_candidates_index.html.slim
Merge pull request #198 from Henry-CF/candidate

fix access denied issue when a hiring manager assign multi candidates to opening.