Update: Allow the bin/div to read $PORT from .env

Rather than defaulting to 3002, read the PORT=xxxx value from
a local `.env` file

This ensures that generated emails and script will work if a
dev uses 3000, 4050, etc in their local .env file

Procfile.dev

@@ -1,4 +1,4 @@
-web: bin/rails server -p 3002
+web: bin/rails server -p ${PORT:-3002}
 worker: bundle exec sidekiq
 js: yarn build --watch
 css: yarn build:css --watch