config(issues): adds issue template for contributors

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,22 @@
+<!--- Make sure to add a descriptive title in the field above! E.g. "The header title on the homepage has the wrong color"  -->
+
+## Current Behavior
+<!--- Tell us what happens on the website that shouldn't happen. E.g. "Currently the header title is green." -->
+
+## Expected Behavior
+<!--- Tell us what should happen instead - how would you expect this to see fixed? E.g. "The header title should be Ember orange." -->
+
+## Steps to Reproduce
+<!--- Please let other contributors know how they can reproduce the issue in several steps. E.g. "1. visit emberjs.com 2. You will see the green header title." -->
+1.
+2.
+3.
+
+## Environment
+<!--- Please provide any technical details that might be relevant for the reproduction of this issue. E.g. "seen on emberjs.com, Windows 7, Internet Explorer 10" -->
+
+## Possible Solution
+<!--- This is optional. If you have an idea how this could be fixed, please let contributors know here. -->
+
+## Sources
+<!--- This is optional. If you can provide a screenshot or a screen recording of something that needs to be improved, please paste these here. -->