text: CREATE TABLE proof_of_service_docs
  (
      id uuid primary key,
      payment_request_id uuid NOT NULL
          constraint proof_of_service_docs_payment_request_id_fkey references payment_requests,
      upload_id uuid NOT NULL
          constraint proof_of_service_docs_upload_id_fkey references uploads,
      created_at timestamp without time zone NOT NULL,
      updated_at timestamp without time zone NOT NULL,
      constraint proof_of_service_docs_unique_key unique (payment_request_id, upload_id)
  )