Move requires into the relevant tasks

Rakefile

 require 'dotenv/load'
-require 'sassc'
-
-require_relative './db/migrate'
-require_relative './db/scrape'
 
 task 'migrate' do
+  require_relative './db/migrate'
+
   migrate
 end
 
 task 'scrape' do
+  require_relative './db/scrape'
+
   should_log = ENV['APP_ENV'] == 'development' || ARGV.include?('--log')
   scraper = Scraper.new(log: should_log)
   scraper.scrape
 end
 
 task 'build' do
+  require 'sassc'
+
   scss = File.read('./web/assets/style.scss')
   css = SassC::Engine.new(scss, style: :compressed).render
   puts 'Writing web/public/style.css'