Updated README instructions for setting up PostgreSQL on dev. Changed database.yml database configuration to use PostgreSQL on dev.
Updated Gemfile for PostgreSQL.
Corrected a step in PostgreSQL for dev setup. Clarified other steps.
Updated README and config/database.yml to better reflect default postgres.app usage.
Merge pull request #20 from crzrcn/database-change

Updated README instructions for setting up PostgreSQL on dev. Changed da...