add reference to dockerhub image

DOCKER.md

@@ -4,22 +4,25 @@
 We also provide a Dockerfile to run MorphQ in a Docker container.
 
 1. To build the Docker image, run the following command:
-```bash
-docker build -t morphq .
-```
-
+    ```bash
+    docker build -t morphq .
+    ```
 1. To run the Docker container, run the following command:
+    ```bash
+    docker run -it --rm -p 8888:8888 morphq
+    ```
+
+Optionally: To avoid the build process, you can also use the ready made Docker image from Docker Hub:
 ```bash
-docker run -it --rm -p 8888:8888 morphq
+docker run -it --rm -p 8888:8888 mattepalte/morphq:latest
 ```
 
-
 ### LEVEL 1: Reproduce the Paper Figures
 
 1. To run the run the notebook in the Docker container, run the following command:
-```bash
-jupyter notebook --allow-root --no-browser --ip=0.0.0.0 --port=8888
-```
+    ```bash
+    jupyter notebook --allow-root --no-browser --ip=0.0.0.0 --port=8888
+    ```
 1. Then open the link that is printed in the terminal in your browser. Note that the link will look something like this: `http://127.0.0.1:8888/?token=6819f647f19859d9e92013a41f52f49d6ffed633e7b68657`.
 1. Open the `notebooks/RQs_Reproduce_Analysis_Results_Level_1.ipynb` notebook.
 1. Run the notebook top-to-bottom.