Following the Tutorial was not going smoothly

[F4bwDP6a6W]

# config/environment.rb
config.gem "authlogic"

got this error:

undefined local variable or method "config" for main:Object

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script/generate session user_session

Got this error:

Could not find generator 'session'. Maybe you meant 'assets' or 'helper' or 'task'

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is there any special requirement for this Tutorial ?

And script/generate is not in my environment, I used rails g instead.
Is that correct?