Update issue templates

.github/ISSUE_TEMPLATE/bug_report.md

@@ -7,32 +7,29 @@ assignees: ''
 
 ---
 
-**Describe the bug**
-A clear and concise description of what the bug is.
-
-**To Reproduce**
-Steps to reproduce the behavior:
-1. Go to '...'
-2. Click on '....'
-3. Scroll down to '....'
-4. See error
-
-**Expected behavior**
-A clear and concise description of what you expected to happen.
-
-**Screenshots**
-If applicable, add screenshots to help explain your problem.
-
-**Desktop (please complete the following information):**
- - OS: [e.g. iOS]
- - Browser [e.g. chrome, safari]
- - Version [e.g. 22]
-
-**Smartphone (please complete the following information):**
- - Device: [e.g. iPhone6]
- - OS: [e.g. iOS8.1]
- - Browser [e.g. stock browser, safari]
- - Version [e.g. 22]
-
-**Additional context**
-Add any other context about the problem here.
+When reporting a bug, please **try** to provide as much information as possible.
+
+ * Plugin version used.
+ * Jenkins version used.
+ * Your configuration.
+   * Variables configured, names, expressions...
+   * Pipeline script (See Pipeline section in README)
+ * Build job log
+ * Post content received. It can be found in the job execution log. People using GitHub often forget to set the content type in "Manage webhook" when configuring the webhook at GitHub.
+ * A `curl` command and its response.
+ * Expected result and actual result.
+
+You may also have a look at the test cases as they should answer the most common questions:
+
+  https://github.com/jenkinsci/generic-webhook-trigger-plugin/tree/master/src/test/resources/org/jenkinsci/plugins/gwt/bdd
+
+If you are fiddling with expressions, you may want to checkout:
+
+* [This JSONPath site](http://jsonpath.herokuapp.com/)
+* [This XPath site](http://www.freeformatter.com/xpath-tester.html)
+* [This regexp site](https://jex.im/regulex/)
+
+A Curl command can look something like this:
+```
+curl -v -H "Content-Type: application/json" -X POST -d '{ "app":{ "name":"GitHub API", "url":"http://developer.github.com/v3/oauth/" }}' http://localhost:8080/jenkins/generic-webhook-trigger/invoke?token=sometoken
+```