I'm having trouble with the following command on page 196 in the Ruby script console:

ruby script/generate migration AddPermalinkToStories
Every time, I get the same error message:
SyntaxError: compile error
(irb): parse error, unexpected tIDENTIFIER, expecting kDO or '{' or '('

I have tried to change my spacing, adding parentheses, braces, etc. but get the same error message.

What's wrong?

Thanks in advance.