Update README.md

I added more info to containerized section
- Git Clone, this is the most easy way to get Dockerfile, docker-compose.yaml and package.json(i forget this file and i can't build the image)
- Build the image, to check is every step is going okey, if something failed, people can see where step is failing instead of running from start to end in one run
- run container, the same step as the original readme

README.md

@@ -14,7 +14,17 @@ A self hostable service for sending ebooks to a Kobo or Kindle ereader through t
 6. Start this service by running: `$ npm start` and access it on HTTP port 3001
 
 ### Containerized
-
-1. Have Docker installed
-2. Run `$ docker compose up`
-3. Access the service on HTTP port 3001
+1. You need [Docker](https://www.docker.com/) and [docker-compose](https://docs.docker.com/compose/) installed
+2. Clone this repo (you need Dockerfile, docker-compose.yaml and package.json in the same directory)
+```
+git clone https://github.com/daniel-j/send2ereader.git
+```
+3. Build the image
+```
+docker compose build
+```
+4. run container (-d to keep running in the background)
+```
+docker compose up -d
+```
+5. Access the service on HTTP, default port 3001 (http://localhost:3001)