diff --git a/Gemfile.lock b/Gemfile.lock
index 2763e9a..9d0b7ad 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -66,13 +66,16 @@ GEM
     parallel (1.21.0)
     parser (3.0.2.0)
       ast (~> 2.4.1)
+    psych (4.0.3)
+      stringio
     public_suffix (4.0.6)
     racc (1.5.2)
     rack (2.2.3)
     rainbow (3.0.0)
     rake (13.0.1)
     rchardet (1.8.0)
-    rdoc (6.3.2)
+    rdoc (6.4.0)
+      psych (>= 4.0.0)
     regexp_parser (2.1.1)
     rest-client (2.1.0)
       http-accept (>= 1.7.0, < 2.0)
@@ -115,6 +118,7 @@ GEM
     simplecov-rcov (0.2.3)
       simplecov (>= 0.4.1)
     simplecov_json_formatter (0.1.3)
+    stringio (3.0.1)
     thread_safe (0.3.6)
     unf (0.1.4)
       unf_ext