Added Docker support.

The only change required to the core code was a modification to the root detection routine, to exempt Docker containers from the --asroot requirement.

To build the container:
$ docker build -t ckan .

To use the container to update all mods:
$ docker run --rm -v ${KSPDIR}:/kspdir ckan

To use the container to install MechJeb:
$ docker run --rm -v ${KSPDIR}:/kspdir ckan install MechJeb

Both of the last two lines require that the ${KSPDIR} value be set.

There is a docker-compose.yml supplied which will automatically do this for Linux users.

To use the YAML file to build the container:
$ docker-compose build ckan

To use the YAML file to update all mods:
$ docker-compose run --rm ckan

To use the YAML file to install MechJeb
$ docker-compose run --rm ckan install MechJeb

Cmdline/Main.cs

@@ -6,6 +6,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.IO;
 using System.Linq;
 using System.Reflection;
 using System.Runtime.InteropServices;
@@ -79,7 +80,10 @@ public static int Main(string[] args)
             user = new ConsoleUser(options.Headless);
             CheckMonoVersion(user, 3, 1, 0);
 
-            if ((Platform.IsUnix || Platform.IsMac) && CmdLineUtil.GetUID() == 0)
+            // Processes in Docker containers normally run as root.
+            // If we are running in a Docker container, do not require --asroot.
+            // Docker creates a .dockerenv file in the root of each container.
+            if ((Platform.IsUnix || Platform.IsMac) && CmdLineUtil.GetUID() == 0 && !File.Exists("/.dockerenv"))
             {
                 if (!options.AsRoot)
                 {

Dockerfile

@@ -0,0 +1,30 @@
+FROM mono
+RUN echo '#!/bin/bash\n\
+  chown --reference=/kspdir/GameData -R /kspdir\n\
+' >> /root/cleanup.sh
+RUN chmod +x /root/cleanup.sh
+RUN echo 'trap /root/cleanup.sh EXIT\n\
+  ckan()\n\
+  {\n\
+    mono /build/CmdLine.exe "$@" --kspdir /kspdir --headless\n\
+  }\n\
+  ckan update\n\
+' >> /root/.bashrc
+RUN echo '#!/bin/bash\n\
+  source /root/.bashrc\n\
+  ckan scan\n\
+  if [ "$#" -ne 0 ]; then\n\
+    ckan $@\n\
+  else\n\
+    ckan upgrade --all\n\
+  fi\n\
+' >> /root/entrypoint.sh
+RUN chmod +x /root/entrypoint.sh
+RUN apt-get -y update && apt-get -y install libcurl4-openssl-dev
+RUN mkdir /kspdir
+VOLUME ["/kspdir"]
+COPY . /source
+WORKDIR /source
+RUN nuget restore -NonInteractive
+RUN xbuild /property:Configuration=Release /property:OutDir=/build/
+ENTRYPOINT ["/root/entrypoint.sh"]

docker-compose.yml

@@ -0,0 +1,6 @@
+version: "2"
+services:
+    ckan:
+        build: .
+        volumes:
+            - ~/.steam/steam/steamapps/common/Kerbal Space Program/:/kspdir