feat: add instruction guide (#6)

Author: pranc1ngpegasus

README.md

@@ -1 +1,16 @@
 # Docker base image for [playwright-go](https://github.com/playwright-community/playwright-go)
+
+# Instruction
+
+To use this base image, please specify `DriverDirectory` to `/root/.cache`.
+Also, we are recommend to specify `SkipInstallBrowsers` to `true`.
+
+```go
+pw, err := playwright.Run(&playwright.RunOptions{
+	DriverDirectory:     "/root/.cache",
+	SkipInstallBrowsers: true,
+})
+if err != nil {
+	return nil, fmt.Errorf("failed to start playwright: %w", err)
+}
+```