Change database backend to PostgreSQL

* Bundle pg gem
* Add a database config file sample

config/database.yml

@@ -1,25 +0,0 @@
-# SQLite version 3.x
-#   gem install sqlite3
-development:
-  adapter: sqlite3
-  database: db/development.sqlite3
-  pool: 5
-  timeout: 5000
-
-# Warning: The database defined as "test" will be erased and
-# re-generated from your development database when you run "rake".
-# Do not set this db to the same as development or production.
-test: &test
-  adapter: sqlite3
-  database: ':memory:'
-  pool: 5
-  timeout: 5000
-
-production:
-  adapter: sqlite3
-  database: db/production.sqlite3
-  pool: 5
-  timeout: 5000
-
-cucumber:
-  <<: *test

config/database.yml.sample

@@ -0,0 +1,20 @@
+common: &common
+  adapter: postgresql
+  encoding: unicode
+  pool: 5
+  username: scube
+
+development:
+  <<: *common
+  database: scube_development
+
+test: &test
+  <<: *common
+  database: scube_test
+
+production:
+  <<: *common
+  database: scube_production
+
+cucumber:
+  <<: *test