added issue_template in markdown

Author: manu-chroma

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,33 @@
+Issue tracker is a tool to address bugs in cwltool (reference implementation) itself.
+Please use the [Gitter channel](https://gitter.im/common-workflow-language/common-workflow-language) or [Biostars forum](https://www.biostars.org/) 
+for general questions about using cwltool to create/run workflows or issues not related to cwltool.
+
+If you'd like to report a bug, fill out the template below and provide
+any extra information that may be useful / related to your problem.
+Ideally, you create an [MCVE](http://stackoverflow.com/help/mcve) reproducing
+the problem before opening an issue to ensure it's not caused by something in
+your code.
+
+---
+
+## Expected Behavior
+Tell us what should happen
+
+## Actual Behavior
+Tell us what happens instead
+
+## Workflow Code
+```
+Paste the template code (ideally a minimal example) that causes the issue
+
+```
+
+## Full Traceback
+```pytb
+Paste the full traceback in case there is an exception
+Run the workflow with ``--debug`` flag for more verbose logging 
+```
+
+## Your Environment
+* cwltool version: 
+Check using ``cwltool --version``