Adding internal migrations code for smd to use

internal/pgmigrate/migrations.go

@@ -0,0 +1,42 @@
+package pgmigrate
+
+import (
+	"database/sql"
+
+	"github.com/golang-migrate/migrate/v4"
+	"github.com/golang-migrate/migrate/v4/database/postgres"
+	_ "github.com/golang-migrate/migrate/v4/source/file"
+	_ "github.com/lib/pq"
+)
+
+func DBConnect(dbDSN string) (*sql.DB, error) {
+	db, err := sql.Open("postgres", dbDSN)
+	if err != nil {
+		return nil, err
+	}
+	//ensure the database is accessible
+	err = db.Ping()
+	if err != nil {
+		return db, err
+	}
+	return db, nil
+}
+
+func ApplyMigrations(migrations_dir string, db *sql.DB) error {
+	dbDriver, err := postgres.WithInstance(db, &postgres.Config{})
+	if err != nil {
+		return err
+	}
+	m, err := migrate.NewWithDatabaseInstance(
+		"file://"+migrations_dir,
+		"postgres", dbDriver)
+	if err != nil {
+		return err
+	}
+	defer m.Close()
+	err = m.Up()
+	if err != nil && err != migrate.ErrNoChange {
+		return err
+	}
+	return nil
+}