[Readme] Mongo API - setSlaveOk

[Ratatoeskr]

In the readme you wrote

db.setSlaveOk(1);

But it doesn't work. I found out that the correct usage is

db.getMongo().setSlaveOk()

like it is documented here: https://docs.mongodb.com/manual/reference/method/Mongo.setSlaveOk/

[paltaa]

or db.setSlaveOk(true);