Add rake tasks for create, drop and setup

This commit adds rake tasks for `db:create`, `db:drop` and `db:setup`,
corresponding to the same tasks from Rails. This commit also correctly
sets AR's configuration.
Add rake task for seeding
Default config/database.yml needs to be fetched from the pwd
Merge pull request #19 from popox/master

Default config/database.yml fetched from the pwd
Add binstubs
Bump to 1.2.4

Concerns #19
Fix specs
Fix bug with older versions of ActiveRecord

`ActiveRecord::Migrator.migrations_path` exists in all versions of
ActiveRecord, so we should better use that.

Fixes #20
Bump to 1.2.5
Flickr handle: @m_janko => @jankomarohnic
Merge pull request #12 from newaperio/master

Update migration generator and add rake tasks
Bump to 1.3

Concerns #12
Update README to include new rake tasks

This commit merely adds the rake tasks to the README list that were
added in #12, including create, drop, seed and setup.
Merge pull request #22 from newaperio/lleger-update-readme

Update README to include new rake tasks
Add db:test:prepare, which emulates Railtie implementation.
Merge pull request #23 from atombender/master

Add db:test:prepare
Bump to 1.4.0

Concerns #23
allow for dumping sql
Merge pull request #25 from icambron/dump_structure

allow for dumping sql
Bump to 1.5.0

Concerns #25