create ISSUE_TEMPLATE.md

.github/ISSUE_TEMPLATE.md

+The template below is mostly useful for bug reports and support questions.
+Feel free to remove anything which doesn't apply to you and add more information where it makes sense.
+
+# Required information
+
+ * Distribution:
+ * Distribution version:
+ * The output of
+   * `lxc-start --version`
+   * `lxc-checkconfig`
+   * `uname -a`
+   * `cat /proc/self/cgroups`
+   * `cat /proc/1/mounts`
+
+# Issue description
+
+A brief description of what failed or what could be improved.
+
+# Steps to reproduce
+
+ 1. Step one
+ 2. Step two
+ 3. Step three
+
+# Information to attach
+
+ - [ ] any relevant kernel output (`dmesg`)
+ - [ ] container log (The <log> file from running `lxc-start -n <c> -l <log> -o DEBUG`)
+ - [ ] the containers configuration file