Sequelize with postgres defaults to mysql

I'm setting up Sequelize to manage postgres in a Node.js app.

I've required sequelize-postgres, as well as declared 'postgres' in the dialect attr when instantiating a new Sequelize object. But for some reason, it defaults to using mysql.

Exact error message:

/Users/...project/node_modules/sequelize/lib/dialects/mysql/connector-manager.js:306
    var connection = mysql.createConnection(connectionConfig);
                           ^
TypeError: Cannot call method 'createConnection' of undefined
    at module.exports.connect (.../node_modules/sequelize/lib/dialects/mysql/connector-manager.js:306:28)
    at Object.pool.Pooling.Pool.create 

(.../node_modules/sequelize/lib/dialects/mysql/connector-manager.js:131:19)
    at createResource (.../node_modules/sequelize/node_modules/generic-pool/lib/generic-pool.js:258:13)
    at dispense (.../node_modules/sequelize/node_modules/generic-pool/lib/generic-pool.js:250:9)
    at Object.me.acquire (.../node_modules/sequelize/node_modules/generic-pool/lib/generic-pool.js:316:5)
    at null.fct (.../node_modules/sequelize/lib/dialects/mysql/connector-manager.js:241:19)
    at null.<anonymous> (.../node_modules/sequelize/lib/emitters/custom-event-emitter.js:24:18)
    at processImmediate [as _immediateCallback] (timers.js:336:15)

Any help is appreciated thank you!