Specify price elasticity for each tier

[christophertull]

Add a way to specify price elasticity of demand for each tier.

This could be as simple as another box next to the tiers where price elasticities can be specified.

Populate the box with reasonable default values. These could probably be pulled from the economics literature?

[patwater]

Good idea to have more granular price elasticity. There also could be more detail on the tool though maybe that's not a UI information on the tool thing though rather a UX more in depth how to video and user guide documentation.

"Price elasticity of demand
(0 means no price response)"