Route for accepting an application invitation.

- Domain method for enabling an application role.
- Updated ApplicationRole model `history` property so that it serializes
  the `status` correctly

atst/routes/applications/__init__.py

@@ -6,6 +6,7 @@ from . import index
 from . import new
 from . import settings
 from . import team
+from . import invitations
 from atst.domain.environment_roles import EnvironmentRoles
 from atst.domain.exceptions import UnauthorizedError
 from atst.domain.authz.decorator import user_can_access_decorator as user_can

atst/routes/applications/invitations.py

@@ -0,0 +1,15 @@
+from flask import redirect, url_for, g
+
+from . import applications_bp
+from atst.domain.invitations import ApplicationInvitations
+
+
+@applications_bp.route("/applications/invitations/<token>", methods=["GET"])
+def accept_invitation(token):
+    invite = ApplicationInvitations.accept(g.current_user, token)
+
+    return redirect(
+        url_for(
+            "portfolios.show_portfolio", portfolio_id=invite.application.portfolio_id
+        )
+    )