Use dotenv

Gemfile

@@ -6,6 +6,7 @@ gem 'rails', '>= 5.0.0.beta1', '< 5.1'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
 # gem 'jbuilder', '~> 2.0'
 # Use Puma as the app server
+gem 'dotenv-rails'
 gem 'fluent-logger'
 gem 'puma'
 gem 'rack-heartbeat'

Gemfile.lock

@@ -97,6 +97,10 @@ GEM
     crack (0.4.3)
       safe_yaml (~> 1.0.0)
     diff-lcs (1.2.5)
+    dotenv (2.1.0)
+    dotenv-rails (2.1.0)
+      dotenv (= 2.1.0)
+      railties (>= 4.0, < 5.1)
     em-hiredis (0.3.0)
       eventmachine (~> 1.0)
       hiredis (~> 0.5.0)
@@ -265,6 +269,7 @@ DEPENDENCIES
   byebug
   capistrano-rails
   capistrano3-unicorn
+  dotenv-rails
   factory_girl_rails
   flay
   fluent-logger

config/deploy.rb

@@ -26,6 +26,7 @@
 # set :linked_files, fetch(:linked_files, []).push('config/database.yml', 'config/secrets.yml')
 
 # Default value for linked_dirs is []
+set :linked_files, fetch(:linked_files, []).push('.env')
 set :linked_dirs, fetch(:linked_dirs, []).push('log', 'tmp/pids', 'tmp/cache', 'tmp/sockets', 'vendor/bundle', 'public/system')
 
 # Default value for default_env is {}