Remove outdated deployment tip.

Conflicts:
	guides/content/developer/deployment/deployment_tips.markdown
Fix N+1 on Shipment#to_package call to variant from Differentiator

On checkout/delivery page, a page refresh calls out to the
`Stock::Differentiator`, which loads a variant from each `inventory_unit`

The fix eliminates N+1 sql select for each variant.

fixes #5775
Relaxing acts_as_list dependency.

0.5.0 is currently the latest.

fixes #5779