Enable deployment with both mysql & postgres gem #355

Shellycloud deployment will go postal if there is no 'pg' gem in our
Gemfile, so we'll switch to postgres in our live environment and leave
the development environment with MySQL until #364 is resolved.

Gemfile

@@ -5,9 +5,6 @@ gem 'rake', '~> 10.1.1'
 
 gem 'thin', '~> 1.6.1'
 
-# Databases
-gem 'mysql2', '~> 0.3.13'
-
 # Memcache Store
 # DO NOT UPGRADE THIS
 # We need exactly this version, because
@@ -127,6 +124,8 @@ group :development do
 end
 
 group :test, :development do
+  # Use MySQL for local setups + travis (as long as #364 is open)
+  gem 'mysql2', '~> 0.3.13'
   gem 'database_cleaner', '1.2.0'
   gem 'rspec-rails',  '~> 3.0.0.beta1'
   gem 'factory_girl_rails', '~> 4.2'
@@ -139,6 +138,8 @@ group :test, :development do
 end
 
 group :production do
+  # Move pg gem to global block, once we're done with #364
+  gem 'pg', '~> 0.17.1'
   gem 'shelly-dependencies'
 end
 

Gemfile.lock

@@ -279,6 +279,7 @@ GEM
       multi_json (~> 1.3)
       omniauth-oauth (~> 1.0)
     orm_adapter (0.5.0)
+    pg (0.17.1)
     polyamorous (0.6.4)
       activerecord (>= 3.0)
     polyglot (0.3.4)
@@ -482,6 +483,7 @@ DEPENDENCIES
   omniauth (~> 1.1.3)
   omniauth-github (~> 1.1.0)
   omniauth-twitter (~> 1.0.1)
+  pg (~> 0.17.1)
   pry-rails
   quiet_assets (~> 1.0.2)
   rails (~> 4.0.3)