added database to issue template

.github/ISSUE_TEMPLATE.md

@@ -1,6 +1,7 @@
 Please include the following information when submitting a bug report/issue:
 
 * NodeBB version and git hash (to find your git hash, execute `git rev-parse HEAD` from the main NodeBB directory)
+* Database (mongo or redis) and it's version.
 * Exact steps to cause this issue
     1. First I did this...
     2. Then, I clicked on this item...
@@ -9,4 +10,4 @@ Please include the following information when submitting a bug report/issue:
 * What happened instead
     * e.g. Instead, I got *zyx* and NodeBB set fire to my house
 
-Thank you!
+Thank you!