Add github issue template. (#225)

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,26 @@
+<!--
+	Please note: GitHub issues should only be used for feature requests and
+	bug reports. For general usage/help/discussions, please refer to one of:
+
+	- #prometheus on freenode
+	- the Prometheus Users list: https://groups.google.com/forum/#!forum/prometheus-users
+
+	For bug reports, please fill out the below fields and provide as much detail
+	as possible about your issue.  For feature requests, you may omit the
+	following template.
+-->
+### Host operating system: output of `uname -a`
+
+### mysqld_exporter version: output of `mysqld_exporter --version`
+<!-- If building from source, run `make` first. -->
+
+### MySQL server version
+
+### mysqld_exporter command line flags
+<!-- Please list all of the command line flags -->
+
+### What did you do that produced an error?
+
+### What did you expect to see?
+
+### What did you see instead?