func (app *App) InstanceEnvs(serviceName, instanceName string) map[string]bind.EnvVar {
	envs := make(map[string]bind.EnvVar)
	for _, env := range app.ServiceEnvs {
		if env.ServiceName == serviceName && env.InstanceName == instanceName {
			envs[env.Name] = env.EnvVar
		}
	}
	return envs
}
func (app *App) InstanceEnvs(serviceName, instanceName string) map[string]bind.EnvVar {
	envs := make(map[string]bind.EnvVar)
	for _, env := range app.ServiceEnvs {
		if env.ServiceName == serviceName && env.InstanceName == instanceName {
			envs[env.Name] = env.EnvVar
		}
	}
	return envs
}
// InstanceEnvs returns a map of environment variables that belongs to the
// given service and service instance.