Update installation.md to quickstart Linux users (CMU-Perceptual-Computing-Lab#1351)

neonb88 · gineshidalgo99 · commit c57b398635ba · 2019-09-10T20:09:37.000-04:00
diff --git a/doc/installation.md b/doc/installation.md
@@ -55,9 +55,13 @@ We add links to some community-based work based on OpenPose. Note: We do not sup
 
 - Docker Images. For questions and more details, read and post ONLY on [issue thread #347](https://github.com/CMU-Perceptual-Computing-Lab/openpose/issues/347).
     - Dockerfile working also with CUDA 10:
-        - [Link 1](https://github.com/esemeniuc/openpose-docker), it claims to also include Python support. Read and post ONLY on [issue thread #1102](https://github.com/CMU-Perceptual-Computing-Lab/openpose/issues/1102).
-        - [Link 2](https://github.com/ExSidius/openpose-docker/blob/master/Dockerfile).
-        - [Link 3](https://cloud.docker.com/repository/docker/exsidius/openpose/general).
+        - Option 1:
+            - 1. (if necessary) Install the latest version of docker (There are extra steps, but if you're on Ubuntu, the main one is `sudo apt-get install docker-ce`.  Other steps can be found [here](https://phoenixnap.com/kb/how-to-install-docker-on-ubuntu-18-04) )
+            - 2. `docker pull docker pull exsidius/openpose`
+            - 3. [more details](https://cloud.docker.com/repository/docker/exsidius/openpose/general) 
+        - [Link 2](https://github.com/esemeniuc/openpose-docker), it claims to also include Python support. Read and post ONLY on [issue thread #1102](https://github.com/CMU-Perceptual-Computing-Lab/openpose/issues/1102).
+        - [Link 3](https://github.com/ExSidius/openpose-docker/blob/master/Dockerfile).
+        - [Link 4](https://cloud.docker.com/repository/docker/exsidius/openpose/general).
     - Dockerfile working only with CUDA 8:
         - [Dockerfile - OpenPose v1.4.0, OpenCV, CUDA 8, CuDNN 5, Python2.7](https://github.com/tlkh/openpose). Read and post ONLY on [issue thread #1102](https://github.com/CMU-Perceptual-Computing-Lab/openpose/issues/1102).
         - [Dockerfile - OpenPose v1.4.0, OpenCV, CUDA 8, CuDNN 6, Python2.7](https://gist.github.com/moiseevigor/11c02c694fc0c22fccd59521793aeaa6).
