Unify timestamp format used by adapter (#12)

* Unify timestamp format used by adapter

* Refactor and move time formating to reusable function

Author: lafriks

README.md

@@ -83,5 +83,5 @@ docker run -it --rm -p 5433:5432 -e "POSTGRES_USER=rel" -e "POSTGRES_PASSWORD=te
 ### Run tests
 
 ```console
-POSTGRESQL_DATABASE="postgres://rel:test@localhost:5433/rel_test?timezone=Asia/Jakarta" go test ./...
+POSTGRESQL_DATABASE="postgres://rel:test@localhost:5433/rel_test" go test ./...
 ```

postgres.go

@@ -170,7 +170,7 @@ func columnMapper(column *rel.Column) (string, int, int) {
 	case rel.DateTime:
 		typ = "TIMESTAMPTZ"
 		if t, ok := column.Default.(time.Time); ok {
-			column.Default = t.Format("2006-01-02 15:04:05")
+			column.Default = FormatTime(t)
 		}
 	case rel.Int, rel.BigInt, rel.Text:
 		column.Limit = 0

quote.go

@@ -45,6 +45,6 @@ func (c ValueConvert) ConvertValue(v interface{}) (driver.Value, error) {
 	default:
 		return v, nil
 	case time.Time:
-		return v.Truncate(time.Microsecond).Format("2006-01-02 15:04:05.999999999Z07:00:00"), nil
+		return FormatTime(v), nil
 	}
 }

util.go

@@ -0,0 +1,13 @@
+package postgres
+
+import (
+	"time"
+)
+
+// TimeLayout used by PostgreSQL adapter.
+const TimeLayout = "2006-01-02 15:04:05.999999999Z07:00:00"
+
+// FormatTime formats time to PostgreSQL format.
+func FormatTime(t time.Time) string {
+	return t.Truncate(time.Microsecond).Format(TimeLayout)
+}