docs: add Docker build instructions

README.md

@@ -26,6 +26,29 @@ git clone https://github.com/muratmirgun/pretgo
 ```bash
 go install
 ```
+### Or use Dockerfile to generate image and container
+
+```bash
+# inside project
+docker build -t pretgo-local .
+```
+
+### Then use it with json
+```bash
+➜ cat mes.json | docker run -i --rm pretgo-local -format="json"
+```
+
+### Or html
+
+```bash
+➜ cat mes.html | docker run -i --rm pretgo-local -format="html"
+```
+
+### Or xml format
+
+```bash
+➜ cat mes.xml | docker run -i --rm pretgo-local -format="xml"
+```
 
 ## Code Examples