fix: error unmarshal empty app config (#609)

Author: pedronasser

api/datastore/postgres/postgres.go

@@ -8,12 +8,12 @@ import (
 
 	"context"
 
+	"bytes"
 	"github.com/Sirupsen/logrus"
+	"github.com/iron-io/functions/api/datastore/internal/datastoreutil"
 	"github.com/iron-io/functions/api/models"
 	"github.com/lib/pq"
 	_ "github.com/lib/pq"
-	"bytes"
-	"github.com/iron-io/functions/api/datastore/internal/datastoreutil"
 )
 
 const routesTableCreate = `
@@ -185,8 +185,8 @@ func (ds *PostgresDatastore) GetApp(ctx context.Context, name string) (*models.A
 		Name: resName,
 	}
 
-	if err := json.Unmarshal([]byte(config), &res.Config); err != nil {
-		return nil, err
+	if len(config) > 0 {
+		json.Unmarshal([]byte(config), &res.Config)
 	}
 
 	return res, nil
@@ -295,7 +295,6 @@ func (ds *PostgresDatastore) InsertRoute(ctx context.Context, route *models.Rout
 		return err
 	})
 
-
 	if err != nil {
 		return nil, err
 	}
@@ -563,7 +562,6 @@ func (ds *PostgresDatastore) Get(ctx context.Context, key []byte) ([]byte, error
 	return []byte(value), nil
 }
 
-
 func (ds *PostgresDatastore) Tx(f func(*sql.Tx) error) error {
 	tx, err := ds.db.Begin()
 	if err != nil {