diff --git a/manifest.toml b/manifest.toml
index e92e144..14387cf 100644
--- a/manifest.toml
+++ b/manifest.toml
@@ -85,6 +85,8 @@ ram.runtime = "50M"
         # For Ruby
 
         "libjemalloc-dev",
+        "libffi-dev",
+        "libyaml-dev",
         "curl",
         "build-essential",
         "libreadline-dev",