Added ActiveRecord::Base.clear_active_connections! in development mode so the...

Added ActiveRecord::Base.clear_active_connections! in development mode so the database connection is not carried over from request to request. Some databases won't reread the schema if that doesn't happen (I'm looking at you SQLite), so you have to restart the server after each migration (= no fun) [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/branches/1-2-pre-release@5617 5ecf4fe2-1ee6-0310-87b1-e25e094e27de