source/pkger: add readme

Author: hnnsgstfssn

source/pkger/README.md

@@ -0,0 +1,29 @@
+# pkger
+```
+package main
+
+import (
+	"errors"
+	"log"
+
+	"github.com/golang-migrate/migrate/v4"
+	"github.com/markbates/pkger"
+
+	_ "github.com/golang-migrate/migrate/v4/database/postgres"
+	_ "github.com/golang-migrate/migrate/v4/source/pkger"
+	_ "github.com/lib/pq"
+)
+
+func main() {
+	pkger.Include("/module/path/to/migrations")
+	m, err := migrate.New("pkger:///module/path/to/migrations", "postgres://postgres@localhost/postgres?sslmode=disable")
+	if err != nil {
+		log.Fatalln(err)
+	}
+	if err := m.Up(); errors.Is(err, migrate.ErrNoChange) {
+		log.Println(err)
+	} else if err != nil {
+		log.Fatalln(err)
+	}
+}
+```