Add Github Issues template

issue_template.md

@@ -0,0 +1,24 @@
+### Expected behaviour
+
+Tell us what should happen
+
+
+### Actual behaviour
+
+Tell us what happens instead
+
+
+### Steps to reproduce
+
+1.
+2.
+3.
+
+
+### Configuration
+
+- Kanboard version:
+- Database type and version:
+- PHP version:
+- OS:
+- Browser: