datasource/mongo/config.go
func (m *Environment) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var aux struct {
		Env map[string]struct {
			Config `yaml:"mongo"`
		}
	}
	if err := unmarshal(&aux.Env); err != nil {
		return err
	}
	m.Env = make(map[string]Config)
	for env, conf := range aux.Env {
		m.Env[env] = conf.Config
	}
	return nil
}
func (m *Environment) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var aux struct {
		Env map[string]struct {
			Config `yaml:"mongo"`
		}
	}
	if err := unmarshal(&aux.Env); err != nil {
		return err
	}
	m.Env = make(map[string]Config)
	for env, conf := range aux.Env {
		m.Env[env] = conf.Config
	}
	return nil
}
//UnmarshalYAML implements Unmarshaler. Avoid use of env in the YAML file.