diff --git a/Gemfile b/Gemfile
index 9c9ee365..20d6b365 100644
--- a/Gemfile
+++ b/Gemfile
@@ -24,10 +24,12 @@ gem 'rails_12factor', group: :production
 # http://edgeguides.rubyonrails.org/upgrading_ruby_on_rails.html#responders
 gem 'responders', '~> 2.0'
 
-# as the database for Active Record
-# choose only one
+# as supported databases
+# WARNING: please refrain from using sqlite for anything serious as it is not
+#          performant enough
 gem 'mysql2'
-# gem 'pg'
+gem 'pg'
+gem 'sqlite3'
 
 # for tracking data changes
 gem 'paper_trail'
@@ -239,8 +241,6 @@ group :development do
   # for static code analisys
   gem 'rubocop', require: false
   gem 'rubocop-rspec'
-  # as database
-  gem 'sqlite3'
   # to open mails
   gem 'letter_opener'
   # to open mails in browser
diff --git a/Gemfile.lock b/Gemfile.lock
index b8441bf2..a953f4f9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -342,6 +342,7 @@ GEM
     parser (2.5.1.2)
       ast (~> 2.4.0)
     pdf-core (0.2.5)
+    pg (1.1.2)
     phantomjs (2.1.1.0)
     piwik_analytics (1.0.2)
       actionpack
@@ -653,6 +654,7 @@ DEPENDENCIES
   omniauth-google-oauth2
   omniauth-openid
   paper_trail
+  pg
   phantomjs
   piwik_analytics (~> 1.0.1)
   poltergeist