Update issue templates

.github/ISSUE_TEMPLATE/issue-template.md

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+---
+name: issue template
+about: Describe this issue template's purpose here.
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+This is a template to report a bug related to the Redmine issue templates plugin.
+You can fill in any format, freestyle in case report features or questions.
+
+## Summary
+
+
+## Description
+
+
+## Environment
+
+This information is greatly helpful to support quickly.
+You can get this information from Redmine's information page.
+(E.g. http://example.com/admin/info)
+
+- Redmine version
+- Installed plugins
+- Ruby version
+- OS Platform
+- Database (MariaDB, MySQL, PostgreSQL) and its version
+- Rails Env
+
+
+## Visual Proof / Screenshot
+
+When reporting an application error, post the error stack trace that you should find in the **log file** (eg. log/production.log). 
+
+A screenshot would be also helpful.
+
+
+## Expected Results
+
+## Actual Results
+
+## Workaround
+
+Please let me know if you have any workaround.