Tags don't appear in edit page on fork

[tomcardoso]

If you fork a chart, assuming the chart has a tag, the tag label won't show up in the "Tags" dropdown field (until you re-add it). Must be because the ID is not associated with that tag in the Tags collection.

[tomcardoso]

Probably need to add a 'tags.change' call (https://github.com/globeandmail/chart-tool/blob/master/meteor/imports/api/Tags/methods.js#L15-L40) to 'charts.fork (https://github.com/globeandmail/chart-tool/blob/master/meteor/imports/api/Charts/methods.js#L40-L50).