Support non-replica MongoDBs

[edemaine]

isMaster returns only partial information when the MongoDB is not a member of a replica set. In particular, it will return isMaster: true and no primary field (at least on some servers I've tried on). As a result, pick-mongo-primary mongodb://localhost/db returns undefined/db whereas it would ideally return localhost/db.

I know your software is not particularly relevant to such simple databases, but some software such as Kadira uses pick-mongo-primary and it'd be nice to easily use such software on a simple MongoDB without replica sets. Currently I have to bypass pick-mongo-primary.

[markreid]

hey @edemaine i'm not sure what your exact use-case is, but if you have a single instance you can enable a replica set without actually having to add other instances to the set. it's sort of the long way round but it resolves the problem with this library.