adding documentation file for windows compatibility

Author: kapilkd13

windowsdoc.md

@@ -0,0 +1,65 @@
+**Windows Compatible Cwltool**
+Windows Compatible cwltool means that now you can create and run your workflows usinng cwltool on windows under a docker container.
+On windows, all tools and workflows will be executed inside a linux based docker container. If a Docker Container is not provided explicitly(using [Docker Requirement](http://www.commonwl.org/v1.0/CommandLineTool.html#DockerRequirement)) by user, we use a minimal, posix compliant Alpine Docker image which has Bash pre installed as fallback(Default) [Docker Container](https://github.com/frol/docker-alpine-bash).  
+You can also provide your own Default Docker Container using `--default-container` argument.
+
+***Requirements***:
+python 2 or 3, Yes Now we support python 3 too.
+Docker
+
+***Best Practises***:
+You should install nodejs on your system if your Workflow contains [Javascript Expressions](http://www.commonwl.org/v1.0/CommandLineTool.html#InlineJavascriptRequirement).
+
+***Installation***:
+****Using Pip****:
+You can install cwltool on windows using pip
+`pip install cwltool`
+
+****Developing from source****:
+`git clone https://github.com/common-workflow-language/cwltool.git`
+`cd cwltool`
+`python setup.py develop`
+
+***Note:*** In order to test if cwltool has been successfully installed on your windows system, run `cwltool` on your `cmd`. A screen showing help instructions should be there.
+
+***Running Cwltool's Unittest***
+If you want to run cwltool's unit test, go to cwltool's repository on your system and run
+`python setup.py test`
+
+***Running Conformance tests using cwltool***
+Download cwltest using `pip install cwltest`
+Clone `Common-Workflow-language` repository using `git clone https://github.com/common-workflow-language/common-workflow-language.git` 
+change directory using `cd common-workflow-language/v1.0`
+Run Tests with `cwltest --test conformance_test_v1
+0.yaml -j 4 --tool cwltool`, here `-j` arg is used to run multiple tests in parallel.
+
+Installing cwltool on windows is smooth but you may face some problems in setting up Docker. Some of the common issues and their solution are mentioned below.
+
+***Docker doesn't work on windows, even outside cwltool.***
+Make sure you followed all instructions carefully while installing Docker. Especially setting up Environment variables. Consult online Docker community if problem persists.
+
+***You Local Drives are not being Shared with Docker Container.***
+On native Docker for windows(supported by Windows 10):
+On your tray, next to your clock, right-click on Docker, then click on Settings, there you'll find the Shared Drives: Here you can share your Drives with Docker.
+If you encounter a Firewall issue, you can [refer this post](https://blog.olandese.nl/2017/05/03/solve-docker-for-windows-error-a-firewall-is-blocking-file-sharing-between-windows-and-the-containers/).
+
+On Docker Toolbox:
+Docker Toolbox uses Virtualbox to create linux base on which Docker machine runs. Your Docker Container will be created inside Virtualbox. To share you Drives
+in virtualbox, go to ****Virtualbox->settings->shared folders->Machine Folders****
+Here Map your Drives you want to share with your Docker Container. 
+If you want to keep these settings permanent(Recommended!), You should mark `make permanent` checkbox or else these settings will be erased everytime your virtualbox closes.
+
+***In a Docker Container with Shared Drives, few Files are shown on `ls` but most of them doesn't.***
+This means your Drives/Folders are not shared properly. When a path is mentioned in docker, it gets cached. So the few folder names that appear on `ls` is because of that.
+In order to solve this problem follow the previous question.
+
+***Can't create/modify a file in Docker when using cwltool.***
+When folders are shared with docker Container, they inherit their current file access permission. If you can write to a folder(with your current privileges) on your local machine, you should be able to write to that folder inside Docker Container also(provided same user initiated Docker). In all it is a file permission issue.
+
+If you still face some issues setting up Docker on windows, please consult online Docker Community. If the Problem is specific to cwltool, create a issue on cwltool. We would definitely try to help you.
+
+***Workflows with Javascript Expressions occasionally gives Timeout error.***
+For evaluating `Javascript expressions` cwltool looks for Nodejs on your system, in case if it can't find a Nodejs installation it creates a node Docker container to execute JS expressions.
+ In order to avoid waiting forever in case some error occurs, cwltool times out js expression evaluation after timeout period ends. You can provide a custom timeout period using `--eval-timeout` argument, by default its value is 20 sec.
+  So if you face this error, best option is to install Nodejs on your local system. If you can't then use the `--eval-timeout` argument and set a higher timeout value.
+