implemented team-dependent exercise policy

app/policies/exercise_policy.rb

@@ -4,20 +4,27 @@ class ExercisePolicy < AdminOrAuthorPolicy
   end
   private :author?
 
-  [:clone?, :statistics?].each do |action|
-    define_method(action) { admin? || author? }
+  [:clone?, :destroy?, :edit?, :show?, :statistics?, :update?].each do |action|
+    define_method(action) { admin? || author? || team_member? }
   end
 
   [:implement?, :submit?].each do |action|
     define_method(action) { everyone }
   end
 
+  def team_member?
+    @record.team.try(:members, []).include?(@user)
+  end
+  private :team_member?
+
   class Scope < Scope
     def resolve
       if @user.admin?
         @scope.all
+      elsif @user.internal?
+        @scope.where("user_id = #{@user.id} OR public = TRUE OR (team_id IS NOT NULL AND team_id IN (SELECT t.id FROM teams t JOIN internal_users_teams iut ON t.id = iut.team_id WHERE iut.internal_user_id = #{@user.id}))")
       else
-        @scope.where("user_id = #{@user.id} OR public = TRUE")
+        @scope.none
       end
     end
   end