Added Ruby use case

ruby-sinatra/Dockerfile

@@ -0,0 +1,21 @@
+FROM ruby:3.1-alpine
+
+# Install build tools and libraries needed to build native extensions
+RUN apk add --no-cache build-base
+
+# Set the working directory in the container
+WORKDIR /usr/src/app
+
+# Copy the Gemfile and Gemfile.lock into the working directory
+COPY Gemfile Gemfile.lock ./
+
+# Install the gems defined in the Gemfile
+RUN bundle install
+
+# Copy the current directory contents into the container
+COPY . .
+
+EXPOSE 5000
+
+# Run app.rb when the container launches
+CMD ["ruby", "app.rb"]