diff --git a/Gemfile.lock b/Gemfile.lock
index 8cf04771..84a0d822 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -219,7 +219,8 @@ GEM
     mocha (2.7.1)
       ruby2_keywords (>= 0.0.5)
     mutex_m (0.3.0)
-    mysql2 (0.5.6)
+    mysql2 (0.5.7)
+      bigdecimal
     net-imap (0.5.9)
       date
       net-protocol