rename and add more details

Author: Vladimir Kotal

docker/readme.md renamed to docker/README.md

@@ -4,16 +4,22 @@
 
 ## OpenGrok from official source
 
-Directly downloaded from official source:
-https://github.com/oracle/opengrok/releases/
+Built from official source: https://github.com/oracle/opengrok/releases/
 
 You can learn more about OpenGrok at http://oracle.github.io/opengrok/
 
 The container is available from DockerHub at https://hub.docker.com/r/opengrok/docker/
 
 ## When not to use it
 
-This image is simple wrapper around OpenGrok environment. The indexer and the web container are **not** tuned for large workloads. If you happen to have either large source data (e.g. [AOSP](https://en.wikipedia.org/wiki/Android_Open_Source_Project) or the like) or stable service or both, it is advisable to run the service standalone.
+This image is simple wrapper around OpenGrok environment. The indexer and the web container are **not** tuned for large workloads.
+If you happen to have one of the following:
+  - large source data (e.g. [AOSP](https://en.wikipedia.org/wiki/Android_Open_Source_Project) or the like)
+  - stable service
+  - Source Code Management systems not supported in the image (e.g. Perforce,
+    Clearcase, etc.)
+then it is advisable to run OpenGrok standalone or construct your own docker
+image based on the official one.
 
 ## Additional info about the container
 
@@ -26,21 +32,15 @@ synchronize all its repositories (e.g. it will do `git pull` for Git
 repositories).
 
 The indexer/mirroring is set so that it does not log into files.
+Rather, everything goes to standard (error) output. To see how the indexer
+is doing, use the `docker logs` command.
 
 ## How to run
 
 ### From DockerHub
 
     docker run -d -v <path/to/your/src>:/opengrok/src -p 8080:8080 opengrok/docker:latest
 
-### Build image locally
-
-    docker build -t opengrok-dev .
-
-Then run the container,
-
-    docker run -d -v <path/to/your/src>:/opengrok/src -p 8080:8080 opengrok-dev
-
 The container exports ports 8080 for OpenGrok.
 
 The volume mounted to `/opengrok/src` should contain the projects you want to make searchable (in sub directories). You can use common revision control checkouts (git, svn, etc...) and OpenGrok will make history and blame information available.
@@ -72,6 +72,16 @@ http://localhost:8080/
 
 The first reindex will take some time to finish. Subsequent reindex will be incremental so will take signigicantly less time.
 
+### Build image locally
+
+If you want to do your own development, you can build the image yourself:
+
+    docker build -t opengrok-dev .
+
+Then run the container:
+
+    docker run -d -v <path/to/your/src>:/opengrok/src -p 8080:8080 opengrok-dev
+
 ## Inspecting the container
 
 You can get inside a container using the [command below](https://docs.docker.com/engine/reference/commandline/exec/):
@@ -80,4 +90,4 @@ You can get inside a container using the [command below](https://docs.docker.com
 docker exec -it <container> bash
 ```
 
-Enjoy.
+Enjoy.