Foreign keys with Sequelize are not created

Did you add the relation after creating the table ( in the database ) ?
You need .sync({ force: true }) if you modify your scheme's and run your program again. Sequelize will only create the table and all it's references if the table does not exist yet in the database.

Are you calling sync after all associations have been made ?

Are you using InnoDB ?

Oddly enough I can reproduce that, The easiest fix is to define the key manually I think, that's how I solved it, Might be a bug otherwise I'm not sure.

See here: http://sequelizejs.com/docs/latest/associations#block-3-line-24