Add issue template to help people fill tickets

Author: ferd

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,31 @@
+### Pre-Check ###
+
+- If you are filing for a bug, please do a quick search in current issues first
+- For bugs, mention if you are willing or interested in helping fix the issue
+- For questions or support, it helps to include context around your project or problem
+- Think of a descriptive title (more descriptive than 'feature X is broken' unless it is fully broken)
+
+### Environment ###
+
+- Add the result of `rebar3 report` to your message:
+
+```
+$ rebar3 report "my failing command"
+...
+```
+
+- Verify whether the version of rebar3 you're running is the latest release (see https://github.com/erlang/rebar3/releases)
+- If possible, include information about your project and its structure. Open source projects or examples are always easier to debug.
+  If you can provide an example code base to reproduce the issue on, we will generally be able to provide more help, and faster.
+
+### Current behaviour ###
+
+Describe the current behaviour. In case of a failure, crash, or exception, please include the result of running the command with debug information:
+
+```
+DEBUG=1 rebar3 <my failing command>
+```
+
+### Expected behaviour ###
+
+Describe what you expected to happen.