Create ISSUE_TEMPLATE.md

omemo/.github/ISSUE_TEMPLATE.md

+#### General information
+
+Before opening an issue, please read our Wiki
+
+* **Gajim Version:** eg 0.16.5
+* **Plugin Version:** eg 0.8.1
+* **OS:** eg Ubuntu 16.04, Windows 7
+* **Server name:** eg conversations.im, jabber.at or self hosted
+* **Server software:** ejabberd 16.04 or prosody 0.10 (if known)
+* **Installed server modules:** eg MAM
+
+
+#### Steps to reproduce
+
+1. …
+2. …
+
+
+#### Expected result
+
+What is the expected output? What do you see instead?
+
+
+#### Debug output
+
+Please start Gajim with `-l gajim.plugin-system.omemo=DEBUG` and post the log file