Might be a tad late, but remove the \
so that the rails generator looks like:
rails generate scaffold Product title:string description:text image_url:string price:decimal
The \
is used to denote the end of a line in a multiline command and when you use it, hit enter to continue writing on the next line. (^
on windows).
If you've already created the database you can rebuild it using:
rails generate scaffold Product title:string description:text image_url:string price:decimal --force
If like me you found that code in Agile Web Development for Rails 4; the preceding paragraph explains the \
.
Hope that small roadblock didn't push you away from rails all those months ago!