ER-model role identifiers

[Neil Zanella <nzanella cs mun ca>]

Hello,

I have one last suggestion (this time for the ER-model implementation).
Perhaps when a relationship is attached to an entity on both ends we
should be able to label the lines with the role identifiers. For
example when we have a user selling items to users we could have
two role identifiers: seller and buyer.

Thanks!

Neil