Added that rake clone_structure_to_test, db_structure_dump, and purge_test_database tasks now pick up the source database to use from RAILS_ENV instead of just forcing development #424 [Tobias Luetke]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@379 5ecf4fe2-1ee6-0310-87b1-e25e094e27de