diff --git a/Gemfile b/Gemfile
index 6788c00316463f22e608634b50f7142d43ffd750..34faa56283c3aa481356b9283596c673e1eeb1c5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -22,6 +22,7 @@ gem "money-open-exchange-rates"
 gem "multibases"
 gem "multihashes"
 gem "multi_json"
+gem "mutex_m"
 gem "ougai"
 gem "relative_time"
 gem "roda"
diff --git a/schemas b/schemas
index e6f4d5c62df63b96e14c412624869411bcbbc76a..688459dd98ec3edc3e2f7774e3d1e92c84f5c0a5 160000
--- a/schemas
+++ b/schemas
@@ -1 +1 @@
-Subproject commit e6f4d5c62df63b96e14c412624869411bcbbc76a
+Subproject commit 688459dd98ec3edc3e2f7774e3d1e92c84f5c0a5