gopkg.in/mgo.v2 is now unmaintained

[ASankaran]

On July 5th, 2018, gopkg.in/mgo.v2 was marked as unmaintained. github.com/globalsign/mgo is now the primary active fork. No features seem to have been removed from the interface. So we should be able to just change the imports and be okay.

[ASankaran]

globalsign/mgo falls back to json tags when bson tags are not present. Current we do not set bson tags and instead rely on the default behavior of mgo. However we do set json tags. So any records present in the database before switching the mgo implementation will not be compatible with the new mgo implementation.

The changing of the mgo implementation should be done be between March and roughly June when neither HackIllinois nor RP has production systems in operation.

See globalsign/mgo#91 for the exact change details.

[ASankaran]

Might also be worth converting to the official mongo go driver once that has a stable release. https://github.com/mongodb/mongo-go-driver

[jerbob92]

@ASankaran just passing through, but... globalsign/mgo does not use the json tag by default, only when you enable the useJSONTagFallback flag.