diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 63f959b..048af34 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -12,6 +12,4 @@ deploy_application:
     - echo -e "-----BEGIN OPENSSH PRIVATE KEY-----\n$SSH_PRIVATE_KEY\n-----END OPENSSH PRIVATE KEY-----" | ssh-add -
     - mkdir -p ~/.ssh
     - echo -e "Host *\nVerifyHostKeyDNS yes" > ~/.ssh/config
-    - echo "$RAILS_MASTER_KEY" > config/master.key
     - bundle exec cap production deploy
-    - rm -f config/master.key
diff --git a/config/deploy.rb b/config/deploy.rb
index a00a269..721ff51 100644
--- a/config/deploy.rb
+++ b/config/deploy.rb
@@ -9,13 +9,12 @@ append :linked_dirs, 'log', 'tmp/pids', 'tmp/cache', 'tmp/sockets',
        'public/system', 'data', '.bundle', 'docs'
 set :bundle_flags, '--deployment'
 set :bundle_jobs, 1
-set :bundle_env_variables, nokogiri_use_system_libraries: 1
 set :keep_releases, 2
 set :ssh_options, check_host_ip: true
 
 set :default_env,
     rails_env: 'production',
-    rails_master_key: File.read('config/master.key'),
+    rails_master_key: ENV.fetch('RAILS_MASTER_KEY') { File.read('config/master.key') },
     web_concurrency: '1',
     ld_preload: '/usr/lib/libjemalloc.so'