support postgres in production

Gemfile

@@ -11,6 +11,9 @@ gem 'rails', '~> 5.0.7'
 # Use Puma as the app server
 gem 'puma', '~> 3.0'
 
+# Use SQLite as the primary database.
+gem 'sqlite3'
+
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 
@@ -62,9 +65,6 @@ group :production do
 end
 
 group :development, :test do
-  # Use SQLite in development and test.
-  gem 'sqlite3'
-
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'byebug', platform: :mri
 

config/database.yml

@@ -12,12 +12,11 @@ test:
   adapter: sqlite3
   database: db/development.sqlite3
 
+# Use sqlite in production by default. Greenlight supports 
 production:
   <<: *default
-  adapter: postgresql
-  database: greenlight_production  
-  encoding: unicode  
-  username: postgres  
-  password:  
-  host: db 
-
+  adapter: <%= ENV['DB_ADAPTER'] || 'sqlite3' %>
+  host: <%= ENV['DB_HOST'] %>
+  database: <%= ENV['DB_NAME'] || 'db/production/production.sqlite3' %>
+  username: <%= ENV['DB_USERNAME'] %>
+  password: <%= ENV['DB_PASSWORD'] %>