doc: markdown formatting of docker readme (#1140)

indented code snippets by 4 spaces

deployment/dockerfiles/README.md

@@ -5,20 +5,20 @@ Dockerfiles for Sourcetrail
 Build docker images
 -------------------
 
-docker build -t <account>/<reponame>:<tag> <Dockerfile>
+    docker build -t <account>/<reponame>:<tag> <Dockerfile>
 
 
 Upload docker images
 --------------------
 
-docker login
-docker push <account>/<reponame>:<tag>
+    docker login
+    docker push <account>/<reponame>:<tag>
 
 
 Run docker images
 -----------------
 
-docker run -it <image> /bin/bash
+    docker run -it <image> /bin/bash
 
 
 Update Guide
@@ -26,28 +26,28 @@ Update Guide
 
 # delete old docker images
 
-$ docker image ls
-$ docker rmi coatisoftware/centos7_64_qt_llvm:<tag>
-$ docker rmi coatisoftware/centos7_32_qt_llvm:<tag>
+    $ docker image ls
+    $ docker rmi coatisoftware/centos7_64_qt_llvm:<tag>
+    $ docker rmi coatisoftware/centos7_32_qt_llvm:<tag>
 
 # docker clean up
 
-$ docker system prune
+    $ docker system prune
 
 # change library version numbers in docker files
 
 # build and upload docker images with new <tag> e.g. qt591-llvm500:
 
-$ cd deployment/dockerfiles/linux/centos7_64
-$ docker build -t coatisoftware/centos7_64_qt_llvm:<tag> .
+    $ cd deployment/dockerfiles/linux/centos7_64
+    $ docker build -t coatisoftware/centos7_64_qt_llvm:<tag> .
 
-$ docker login
-$ docker push coatisoftware/centos7_64_qt_llvm:<tag>
+    $ docker login
+    $ docker push coatisoftware/centos7_64_qt_llvm:<tag>
 
-$ cd ../centos7_32
-$ docker build -t coatisoftware/centos7_32_qt_llvm:<tag> .
+    $ cd ../centos7_32
+    $ docker build -t coatisoftware/centos7_32_qt_llvm:<tag> .
 
-$ docker push coatisoftware/centos7_32_qt_llvm:<tag>
+    $ docker push coatisoftware/centos7_32_qt_llvm:<tag>
 
 # update <tag> of linux images in .gitlab-ci.yml