Depend on a specific version of Node.js

We're choosing version 18 because if offers support for SSL 3, just
like Ruby 3.1 does.

Note we're symlinking a .nvmrc file as well, in order to make it
compatible with NVM. While the .nvmrc and .node-version files use
different formats, they both support the syntax we're using to
define the version.

The code to install Node.js in the Dockerfile is a simplification of the
code in the Rails Dockerfile template [1].

[1] https://github.com/rails/rails/blob/04c97aec8a/railties/lib/rails/generators/rails/app/templates/Dockerfile.tt#L25

Dockerfile

@@ -13,7 +13,6 @@ RUN apt-get update -qq \
     libpq-dev \
     libxss1 \
     memcached \
-    nodejs \
     pkg-config \
     postgresql-client \
     shared-mime-info \
@@ -28,7 +27,7 @@ RUN adduser --shell /bin/bash --disabled-password --gecos "" consul \
  && adduser consul sudo \
  && echo '%sudo ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers
 
-RUN echo 'Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/bundle/bin"' > /etc/sudoers.d/secure_path
+RUN echo 'Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/bundle/bin:/usr/local/node/bin"' > /etc/sudoers.d/secure_path
 RUN chmod 0440 /etc/sudoers.d/secure_path
 
 # Define where our application will live inside the image
@@ -40,6 +39,13 @@ RUN mkdir -p $RAILS_ROOT/tmp/pids
 # Set our working directory inside the image
 WORKDIR $RAILS_ROOT
 
+# Install Node
+COPY .node-version ./
+ENV PATH=/usr/local/node/bin:$PATH
+RUN curl -sL https://github.com/nodenv/node-build/archive/master.tar.gz | tar xz -C /tmp/ && \
+    /tmp/node-build-master/bin/node-build `cat .node-version` /usr/local/node && \
+    rm -rf /tmp/node-build-master
+
 # Use the Gemfiles as Docker cache markers. Always bundle before copying app src.
 # (the src likely changed and we don't want to invalidate Docker's cache too early)
 COPY Gemfile* ./