Create and view performances

This feature turned out to be several:
*Create a performance
*View a performance
*View the date create and by whom
*Add multiple customers and multiple partners to a performance
*View all customers and partners associated with a performance
*View a list of all performances by customer

@ChristopherThorsen - please take a look
Are you suggesting I add a class definition to the Contact model?  I think I've done that already: 
`  def self.customer`
    `where(organization_type: "Customer")`
  `end`

Or are you suggesting something eles?