Make sure SQLite accept both int and integer as pk (#22)

* Make sure SQLite accept both int and integer as pk

This is the behavior for the others drivers, there is no reason to
discriminate SQLite.

* SQLite: Return an error if the pk type is not supported

translators/sqlite.go

@@ -35,10 +35,12 @@ func (p *SQLite) CreateTable(t fizz.Table) (string, error) {
 	for _, c := range t.Columns {
 		if c.Primary {
 			switch strings.ToLower(c.ColType) {
-			case "integer":
+			case "integer", "int":
 				s = fmt.Sprintf("\"%s\" INTEGER PRIMARY KEY AUTOINCREMENT", c.Name)
 			case "uuid", "string":
 				s = fmt.Sprintf("\"%s\" TEXT PRIMARY KEY", c.Name)
+			default:
+				return "", errors.Errorf("can not use %s as a primary key", c.ColType)
 			}
 		} else {
 			s = p.buildColumn(c)