# Rails new --builder

**URL:** <https://www.ruby-forum.com/t/rails-new-builder/194142>\
**Category:** Rails\
**Created:** [August 31, 2010, 1:48am UTC](https://www.ruby-forum.com/t/rails-new-builder/194142 "2010-08-31T01:48:52Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![3nd3r](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/3/c4cdca/32.png) [@3nd3r](https://www.ruby-forum.com/u/3nd3r)\
**Post date:** [August 31, 2010, 1:48am UTC](https://www.ruby-forum.com/t/rails-new-builder/194142/1 "2010-08-31T01:48:52Z")

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When invoking rails new with the --builder option, I see that you have  
to call the class ::AppBuilder. How can you  
change the source\_root for just a few of the methods?

I want to generate the gemfile from my own template

AppBuilder \< Rails::AppBuilder

def gemfile  
template ‘Gemfile’  
end

end

How can I change the Gemfile template from the AppBuilder and if I  
can’t what is the use of the --builder option?

thanks,

Dominic