Editing existing job with multiple tags clobbers commas

[lnhrdt]

When we edit a job that has multiple tags, the tags in the text field are missing commas. They then get combined into one tag.

Should be:

Currently is:

[tjgrathwell]

It's a regression from upgrading to Rails 4.2 (08bfb014e524570f7cfb554031e2aef0f9e25264), more detail at https://github.com/mbleigh/acts-as-taggable-on/wiki/Add-a-tag-field-to-forms-in-Rails--4.2-and-above

Fix incoming, thanks for reporting!