No more drush cr for Drupal 8 theme development

settings.md

this bit goes in development.services.yml

services:
  cache.backend.null:
    class: Drupal\Core\Cache\NullBackendFactory
parameters:
  twig.config:
    debug: true
    auto_reload: null
    cache: false

please do note that turning off the cache causes twig to compile every template needed for your view on every hit. This can be slowly, turn it back on if you do not need be 100% sure the compiled template is really fresh

this bit goes in development.settings.php

<?php
$settings['container_yamls'][] = DRUPAL_ROOT . '/sites/development.services.yml';
// disable render cache
$settings['cache']['bins']['render'] = 'cache.backend.null';
$settings['cache']['bins']['dynamic_page_cache'] = 'cache.backend.null';

And finally add this at the end of your settings.local.php or settings.php

$development_config = DRUPAL_ROOT . '/sites/development.settings.php';
if (file_exists($development_config)){
  require_once $development_config;
}