Switch back to sqlite test db

http://stackoverflow.com/questions/19493153/rails-4-use-sqlite-memory-db-for-selenium-driven-tests

config/database.yml.example

@@ -14,7 +14,7 @@ development:
 # Do not set this db to the same as development or production.
 test:
   adapter: sqlite3
-  database: ":memory:"
+  database: db/test.sqlite3
   pool: 5
   timeout: 5000