Conditional rendering of relationship for tricky situation

gistfile1.txt

```ruby
class User
  embeds_many :attacker_performance
  embeds_many :defender_performance
  has_many :matches_as_attacker
  has_many :matches_as_defender
end

class AttackerPerformance
  embedded_in :user
  belongs_to :match
  
  field :mobility
  field :attacks
end

class DefenderPerformance
  embedded_in :user
  belongs_to :match
  
  field :balls_stopped
end

class Match
  belongs_to :attacker, class: User, inverse_of: :matches_as_attacker
  belongs_to :defender, class: User, inverse_of: :matches_as_defender
  
  # attacker and defender reports are available through each user only
end

class MatchResource < ApplicationJsonapiSuiteResource

  allow_sideload :attack_performances, type: :has_many, resource: AttackPerformanceArrayResource
    scope do |matches|
      User.in(:'attacker_performance.match_id' => matches.pluck(:id)).map(&:attack_performances)
      # Ideal would be instead of the `User.in(...)   `
      #
      #   context.current_user.attacker_performances
      #
      # but context.current_user is not available :'(
    end
    assigns do |matches, attack_performances|
      matches.each do |match|
      match.set_relation(:attacker_performance, attack_performances.detect { |p| p.match == match }
    end
  end
end

class SerializableMatch < ApplicationJsonapiRbSerializer
  has_one :attacker_performance
end

class SerializableAttackerPerformance < ApplicationJsonapiRbSerializer
  attributes :mobility, :attacks
end
```

# Here I would need to allow sideloading or rendering the attack performance only if the `context.current_user` is the guy who performed the attack