Added libyaml-dev to the Rails Dockerfile example

Author: igor-alexandrov

content/guides/ruby/containerize.md

@@ -67,7 +67,7 @@ FROM base AS build
 
 # Install packages needed to build gems
 RUN apt-get update -qq && \
-    apt-get install --no-install-recommends -y build-essential curl git pkg-config && \
+    apt-get install --no-install-recommends -y build-essential curl git pkg-config libyaml-dev && \
     rm -rf /var/lib/apt/lists /var/cache/apt/archives
 
 # Install JavaScript dependencies and Node.js for asset compilation