Improve development dockerfile and associated readme

Dockerfile

@@ -2,9 +2,9 @@
 # making updates to the accumulo website without requiring the dev
 # to maintain a local ruby development environment.
 
-FROM ruby:3.2.2-slim-bullseye as base
+FROM ruby:3.2.2-slim-bullseye AS base
 
-RUN apt-get update && apt-get install -y --no-install-recommends \
+RUN apt update && apt install -y --no-install-recommends \
     build-essential \
     git \
     curl \
@@ -17,13 +17,14 @@ WORKDIR /mnt/workdir
 # from the mounted directory. But that's not available during the
 # docker build, so we need to copy them in to pre-install the Gems
 
-COPY Gemfile ./Gemfile
-COPY Gemfile.lock ./Gemfile.lock
+COPY Gemfile Gemfile.lock ./
 
 # Gems will be installed under GEM_HOME which is set by the ruby image.
 # See https://hub.docker.com/_/ruby for details.
 
-RUN gem update --system && bundle install && gem cleanup
+RUN gem update --system \
+  && bundle install \
+  && gem cleanup
 
 ENV HOST=0.0.0.0
 ENV PORT=4000

README.md

@@ -109,10 +109,6 @@ Jekyll will print a local URL where the site can be viewed (usually,
 
 ### Testing using Docker environment 
 
-A containerized development environment can be built using the local
-Dockerfile.
-
-
 A containerized development environment can be built using the local
 Dockerfile. You can build it with the following command:
 
@@ -123,7 +119,8 @@ docker build -t webdev .
 This action will produce a `webdev` image, with all the website's build
 prerequisites preinstalled. When a container is run from this image, it
 will perform a `jekyll serve` command with the polling option enabled,
-so that changes you make locally will be immediately reflected.
+so that changes you make locally will be immediately reflected after
+reloading the page in your browser.
 
 When you run a container using the webdev image, your current working
 directory will be mounted, so that any changes made by the build inside
@@ -137,20 +134,22 @@ docker run -d -v "$PWD":/mnt/workdir -p 4000:4000 webdev
 While this container is running, you will be able to review the rendered website
 in your local browser at [http://127.0.0.1:4000/](http://127.0.0.1:4000/).
 
-
 Shell access can be obtained by overriding the default container command.
 
 This is useful for adding new gems, or modifying the Gemfile.lock for updating
 existing dependencies.
 
-When using shell access the local directory must be mounted to ensure
+When using shell access, the local directory must be mounted to ensure
 the Gemfile and Gemfile.lock updates are reflected in your local
 environment so you can create a commit and submit a PR.
 
 ```bash
 docker run -v "$PWD":/mnt/workdir -it webdev /bin/bash
 ```
 
+You may need to manually delete the `_site` or `.jekyll-cache` directories if
+they already exist and are causing issues with the build.
+
 ## Publishing
 
 Changes pushed to our `main` branch will automatically trigger Jekyll to