Update template to Ruby 3.3.6 and watchdog

The image had to move from a base slim image, to one which
also includes build-essential due to the new requirement by
Sinatra to require native gems.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Author: alexellis

README.md

@@ -1,9 +1,13 @@
 ## ruby-http
 
+This template uses [Sinatra internally](https://sinatrarb.com/intro.html), and the slim Docker image for Ruby to keep the image small. A native build toolchain is installed, which still results in a smaller image than the standard Ruby image on the Docker Hub.
+
+Ruby version: 3.3.6.
+
 ### Usage:
 
-```
-faas template pull https://github.com/openfaas-incubator/ruby-http
+```bash
+faas template pull https://github.com/openfaas/ruby-http
 faas new --lang ruby-http homepage
 ```
 

template/ruby-http/Dockerfile

@@ -1,6 +1,15 @@
-FROM openfaas/of-watchdog:0.8.1 as watchdog
-
-FROM ruby:2.7.2-slim-buster
+FROM ghcr.io/openfaas/of-watchdog:0.10.6 as watchdog
+
+FROM ruby:3.3.6-slim
+
+# AE: This step can take a few moments, however the resulting image
+# is half the size of the non-slim image
+RUN apt-get update && apt-get install -qqy \
+    build-essential \
+    libssl-dev \
+    libffi-dev \
+    zlib1g-dev \
+    && rm -rf /var/lib/apt/lists/*
 
 COPY --from=watchdog /fwatchdog /usr/bin/fwatchdog
 RUN chmod +x /usr/bin/fwatchdog

template/ruby-http/Gemfile

@@ -1,3 +1,6 @@
 source 'https://rubygems.org'
 
+gem "nio4r"
 gem "sinatra"
+gem "rackup"
+gem "puma"