Ignore SQLite system indices (#81)

* Ignore SQLite system indices

This resolves an issue where SQLite system indices were re-created when executing `change_column`, which throws an error in SQLite.

* Add underscore to SQLite index filter prefix

translators/sqlite_meta.go

@@ -111,7 +111,9 @@ func (p *sqliteSchema) buildTableData(table *fizz.Table, db *sql.DB) error {
 }
 
 func (p *sqliteSchema) buildTableIndexes(t *fizz.Table, db *sql.DB) error {
-	prag := fmt.Sprintf(`SELECT "seq", "name", "unique", "origin", "partial" FROM pragma_index_list('%s')`, t.Name)
+	// This ignores all internal SQLite keys which are prefixed with `sqlite_` as explained here:
+	// https://www.sqlite.org/fileformat2.html#intschema
+	prag := fmt.Sprintf(`SELECT "seq", "name", "unique", "origin", "partial" FROM pragma_index_list('%s') WHERE "name" NOT LIKE 'sqlite_%%'`, t.Name)
 	res, err := db.Query(prag)
 	if err != nil {
 		return err