Added issues template.

.github/ISSUE_TEMPLATE

@@ -0,0 +1,38 @@
+- [x] I want to submit an issue!
+
+### Environment
+
+- [] Windows 8
+- [] Windows 8.1
+- [] Windows 10
+- [] Windows 10 IoT Core
+- [] Windows Server 2012
+- [] Windows Server 2012 R2
+- [] Windows Server 2016
+
+### I have already...
+
+- [] read the README to be aware of npm gotchas & antivirus issues.
+- [] reviewed the [wiki](https://github.com/coreybutler/nvm-windows/wiki) to make sure my issue hasn't already been resolved.
+- [] verified I'm using an account with administrative privileges.
+- [] searched the issues (open and closed) to make sure this isn't a duplicate.
+- [] made sure this isn't a question about how to use NVM for Windows, since [gitter](https://gitter.im/coreybutler/nvm-windows?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) is used for questions and comments.
+
+### My issue is related to:
+
+- [] settings.txt
+- [] proxy support
+- [] 32 or 64 bit support
+
+### Expected Behavior
+
+Fill me in...
+
+### Actual Behavior
+
+Fill me in...
+
+### Steps to reproduce the problem:
+
+Fill me in...
+