Update atst to atat

atat/routes/applications/invitations.py

@@ -0,0 +1,16 @@
+from flask import redirect, url_for, g
+
+from .blueprint import applications_bp
+from atat.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(
+            "applications.portfolio_applications",
+            portfolio_id=invite.application.portfolio_id,
+        )
+    )