text: Title: Add support for more aggregation features
  Body: ## Problem
  
  <!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] -->
  
  We currently only support aggregating by `count`, prisma [supports aggregation](https://www.prisma.io/docs/reference/api-reference/prisma-client-reference#aggregate) by sum, min, max and avg.
  
  Prisma also supports ordering by the aggregate of relations since [v2.19.0](https://github.com/prisma/prisma/releases/tag/2.19.0)
  
  ## Suggested solution
  
  <!-- A clear and concise description of what you want to happen. -->
  
  Add an `aggregate` action method, reference: [https://www.prisma.io/docs/reference/api-reference/prisma-client-reference#aggregate](https://www.prisma.io/docs/reference/api-reference/prisma-client-reference#aggregate)