Move transcodings initialization to a migration

This will make it run only once, not every
time the transcoding table is empty

db/migration/20200706231659_add_default_transcodings.go

@@ -0,0 +1,43 @@
+package migration
+
+import (
+	"database/sql"
+
+	"github.com/deluan/navidrome/consts"
+	"github.com/google/uuid"
+	"github.com/pressly/goose"
+)
+
+func init() {
+	goose.AddMigration(upAddDefaultTranscodings, downAddDefaultTranscodings)
+}
+
+func upAddDefaultTranscodings(tx *sql.Tx) error {
+	row := tx.QueryRow("SELECT COUNT(*) FROM transcoding")
+	var count int
+	err := row.Scan(&count)
+	if err != nil {
+		return err
+	}
+	if count > 0 {
+		return nil
+	}
+
+	stmt, err := tx.Prepare("insert into transcoding (id, name, target_format, default_bit_rate, command) values (?, ?, ?, ?, ?)")
+	if err != nil {
+		return err
+	}
+
+	for _, t := range consts.DefaultTranscodings {
+		r, _ := uuid.NewRandom()
+		_, err := stmt.Exec(r.String(), t["name"], t["targetFormat"], t["defaultBitRate"], t["command"])
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func downAddDefaultTranscodings(tx *sql.Tx) error {
+	return nil
+}