Display tag statistics for external users on their profile

app/models/concerns/user.rb

@@ -8,6 +8,7 @@ module User
     has_many :exercises, as: :user
     has_many :file_types, as: :user
     has_many :submissions, as: :user
+    has_many :participations, through: :submissions, source: :exercise, as: :user
     has_many :user_proxy_exercise_exercises, as: :user
     has_many :user_exercise_interventions, as: :user
     has_many :interventions, through: :user_exercise_interventions