How to Load Development environment in Rails

I am using rails 3 on ubuntu 10. When i trying to load rails
development environment using Rails Runner command

i am getting this:

Usage: runner [options] ('Some.ruby(code)' or a filename)

   -e, --environment=name Specifies the environment for the
runner to operate under (test/development/production).
                                    Default: development

   -h, --help Show this help message.

You can also use runner as a shebang line for your scripts like this: