diff --git a/.env.example b/.env.example
index a62e2b0a..f79ff3a4 100644
--- a/.env.example
+++ b/.env.example
@@ -1,3 +1,4 @@
+RAILS_GROUPS=assets
 DELEGATE=athshe.sutty.nl
 HAINISH=../haini.sh/haini.sh
 DATABASE=
diff --git a/Gemfile b/Gemfile
index db06827d..01167fa1 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,13 +11,16 @@ gem 'dotenv-rails', require: 'dotenv/rails-now'
 gem 'rails', '~> 6'
 # Use Puma as the app server
 gem 'puma'
-# See https://github.com/rails/execjs#readme for more supported runtimes
-# gem 'therubyracer', platforms: :ruby
-# Use SCSS for stylesheets
-gem 'sassc-rails'
-# Use Uglifier as compressor for JavaScript assets
-gem 'uglifier', '>= 1.3.0'
-gem 'bootstrap', '~> 4'
+
+# Solo incluir las gemas cuando estemos en desarrollo o compilando los
+# assets.  No es necesario instalarlas en producción.
+#
+# XXX: Supuestamente Rails ya soporta RAILS_GROUPS, pero Bundler no.
+if ENV['RAILS_GROUPS']&.include? 'assets'
+  gem 'sassc-rails'
+  gem 'uglifier', '>= 1.3.0'
+  gem 'bootstrap', '~> 4'
+end
 
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