fix(backend): don't crash if redis isn't set, use tx in CreateMember

backend/db/redis.go

@@ -0,0 +1,20 @@
+package db
+
+import (
+	"context"
+	"net"
+
+	"emperror.dev/errors"
+	"github.com/mediocregopher/radix/v4"
+)
+
+var _ radix.Client = (*dummyRedis)(nil)
+
+type dummyRedis struct{}
+
+func (*dummyRedis) Addr() net.Addr { return &net.IPAddr{} }
+func (*dummyRedis) Close() error   { return nil }
+
+func (*dummyRedis) Do(context.Context, radix.Action) error {
+	return errors.Sentinel("this is a dummy client")
+}