Add top-level UserApplicationPermissionPolicy

app/policies/user_application_permission_policy.rb

@@ -0,0 +1,52 @@
+class UserApplicationPermissionPolicy < BasePolicy
+  def index?
+    Pundit.policy(current_user, user).edit?
+  end
+
+  def remove_signin_permission?
+    user.has_access_to?(application) &&
+      (
+        current_user.govuk_admin? ||
+        current_user.publishing_manager? && application.signin_permission.delegatable?
+      )
+  end
+
+  def edit_permissions?
+    remove_signin_permission?
+  end
+
+  def view_permissions?
+    Pundit.policy(current_user, user).edit? &&
+      user.has_access_to?(application)
+  end
+
+  def delete?
+    edit_permissions?
+  end
+
+  def destroy?
+    delete?
+  end
+
+  def show?
+    view_permissions?
+  end
+
+  def edit?
+    edit_permissions?
+  end
+
+  def update?
+    edit_permissions?
+  end
+
+  private
+
+  def user
+    record.user
+  end
+
+  def application
+    record.application
+  end
+end