func Merge(fromMap, ToMap interface{}) interface{}
Merge recursively merges map `fromMap` into map `ToMap`. Any pre-existing values in ToMap are overwritten. Values in fromMap are added to ToMap. From http://stackoverflow.com/questions/40491438/merging-two-json-strings-in-golang
func MergeJSON(object interface{}, additionalJSON []byte) (interface{}, error)
MergeJSON merges the contents of a JSON string into an object representation, returning a new object suitable for translating to JSON.