Unable to load builder with default generator output

[coder2000]

The default location that the generator places the builder class of lib/ isn't loaded automatically by the application and needs to be manually included somewhere. There are are few options:

1. Update the documentation to specify that it needs to be included
2. Add an initializer to the generator that requires the builder
3. Change the generator to put the builder in the app/helpers folder instead

[Spone]

I'd be OK with option 1, option 3 (but maybe with an app/forms folder?), or suggesting both 1 and 3 in the docs.
What do you think @nicolas-brousse?