enh: create an issue template

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,31 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: bug
+assignees: ''
+
+---
+
+## Describe the bug
+
+Describe what the bug is, how it happens, and maybe paste a backtrace if you could get one.
+
+## To Reproduce
+
+If you are **pretty sure** about the cause, or you are **pretty sure** it's a easy fix, or you are **pretty sure** it can be easily reproduced by developers, you can delete this section. Otherwise, write steps to reproduce, and it should start by `$ emacs -Q`.
+
+Steps to reproduce:
+
+1. `$ emacs -Q`
+2. ...
+
+## System information
+
+- OS: 
+- Emacs version: 
+- Are you using the latest version of Citre on master branch: 
+
+## Additional context
+
+Add any other context about the problem here.