feat: versioned migrations (#26)

* enable atlas migrations

* use embedded atlas migrations

* chores

* bad migration example

* tidy

* fix linter issues

* reset migration state

* sort slice before testing

* move temp write logic to migrations package

backend/internal/migrations/migrations.go

@@ -0,0 +1,44 @@
+package migrations
+
+import (
+	"embed"
+	"os"
+	"path/filepath"
+)
+
+// go:embed all:migrations
+var Files embed.FS
+
+// Write writes the embedded migrations to a temporary directory.
+// It returns an error and a cleanup function. The cleanup function
+// should be called when the migrations are no longer needed.
+func Write(temp string) error {
+	err := os.MkdirAll(temp, 0755)
+
+	if err != nil {
+		return err
+	}
+
+	fsDir, err := Files.ReadDir(".")
+	if err != nil {
+		return err
+	}
+
+	for _, f := range fsDir {
+		if f.IsDir() {
+			continue
+		}
+
+		b, err := Files.ReadFile(filepath.Join("migrations", f.Name()))
+		if err != nil {
+			return err
+		}
+
+		err = os.WriteFile(filepath.Join(temp, f.Name()), b, 0644)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}