Add heroku release step

Procfile

@@ -1,3 +1,4 @@
 worker:          bundle exec rake jobs:work
 rabbit_workers:  bin/rails r lib/rabbit_workers.rb
 web:             bundle exec passenger start -p $PORT -e $RAILS_ENV --max-pool-size 2
+release:         bundle exec rake api:build_assets

app/controllers/dashboard_controller.rb

@@ -25,6 +25,25 @@ class DashboardController < ApplicationController
     acc
   end)
 
+  PARCEL_ASSET_LIST = (CSS_INPUTS.values + JS_INPUTS.values)
+    .sort
+    .uniq
+    .map { |x| "frontend" + x }
+    .join(" ")
+
+  PARCEL_HMR_OPTS   = [
+    "--hmr-hostname #{ENV.fetch("API_HOST")}",
+    "--hmr-port 3808"
+  ].join(" ")
+
+  PARCEL_CLI_OUTRO  = [
+    # WHY ARE SOURCE MAPS DISABLED?
+    # https://github.com/parcel-bundler/parcel/issues/2599#issuecomment-459131481
+    # https://github.com/parcel-bundler/parcel/issues/2607
+    # TODO: Upgrade parcel when issue ^ is fixed.
+    "--no-source-maps",
+  ].join(" ")
+
   [:main_app, :front_page, :password_reset, :tos_update].map do |actn|
     define_method(actn) do
       begin

lib/tasks/api.rake

@@ -50,32 +50,27 @@ namespace :api do
     sh "sudo docker-compose up --scale parcel=0"
   end
 
+  def parcel(cmd, opts = " ")
+    intro = [ "node_modules/parcel-bundler/bin/cli.js",
+              cmd,
+              DashboardController::PARCEL_ASSET_LIST,
+              "--out-dir public/dist",
+              "--public-url /dist" ].join(" ")
+    sh [intro, opts, DashboardController::PARCEL_CLI_OUTRO].join(" ")
+  end
+
   desc "Serve javascript assets (via Parcel bundler)"
   task serve_assets: :environment do
-    css    = DashboardController::CSS_INPUTS.values
-    js     = DashboardController::JS_INPUTS.values
-    assets = (js + css)
-      .sort
-      .uniq
-      .map { |x| "frontend" + x }
-      .join(" ")
+    # Clear out cache and previous builds on initial load.
+    sh "rm -rf .cache/ public/dist/"
+    parcel "watch", DashboardController::PARCEL_HMR_OPTS
+  end
 
-      cli = [
-      "node_modules/parcel-bundler/bin/cli.js",
-      "watch",
-      assets,
-      "--out-dir public/dist",
-      "--public-url /dist",
-      "--hmr-hostname #{ENV.fetch("API_HOST")}",
-      "--hmr-port 3808",
-      # WHY ARE SOURCE MAPS DISABLED?
-      # https://github.com/parcel-bundler/parcel/issues/2599#issuecomment-459131481
-      # https://github.com/parcel-bundler/parcel/issues/2607
-      # TODO: Upgrade parcel when issue ^ is fixed.
-      "--no-source-maps",
-    ].join(" ")
-    puts "=== Running: \n#{cli}"
-    sh cli
+  desc "DELETE OLD ASSETS and build javascript/css assets via Parcel bundler"
+  task build_assets: :environment do
+    sh "rm -rf .cache/ node_modules/ public/dist/"
+    sh "npm install"
+    parcel "build"
   end
 
   desc "Reset _everything_, including your database"