Added pt-osc connection adapter

- test that it can be used in database config to establish a connection
  - added testing infrastructure
      - dummy Rails app
      - dependencies
      - rake task
      - test helper
      - test database config
refactor test_spec into test_helper
added Rake task to create test database
Added modification commands to pt-osc adapter

- rename_table
- add_column
- change_column
- rename_column

- added tests