diff --git a/main.go b/main.go
index 8dc0066..e157d2d 100644
--- a/main.go
+++ b/main.go
@@ -57,7 +57,7 @@ func initDatabase(conn *sql.DB) {
 func migrateDatabase(conn *sql.DB, currentVersion int) {
 
 	migrations := []string{
-		"ALTER TABLE history add column workdir varchar(4096)",
+		"ALTER TABLE history add column workdir varchar(4096) DEFAULT ''",
 	}
 
 	if !(len(migrations) > currentVersion) {