ISSUE_TEMPLATE.md: Create with basic instructions

The content of the ISSUE_TEMPLATE.md file will be initially shown
when a new issue is opened. It contains general information about
the project and also the minimally required sections.

Closes coala#312

ISSUE_TEMPLATE.md

@@ -0,0 +1,20 @@
+<!-- Hello! If you're filing a bug, please include every step so as to help us reproduce it on our machines. If you're unsure about how to file an issue, use the issue template. If you need any help regarding usage of coala, check out the documentation or hit us up on chat. You can ignore or delete this text, it is commented and won't appear when the issue is submitted or previewed.
+
+Chat: https://gitter.im/coala/corobo
+Documentation: https://github.com/coala/corobo/blob/master/docs/corobo.rst
+-->
+### Overview Description
+
+# Steps to Reproduce
+
+1.
+2.
+3.
+
+# Actual Results
+
+# Expected Results
+
+# Reproducibility
+
+# Additional Information: