Add ISSUE_TEMPLATE
Add ISSUE_TEMPLATE

BUG=https://github.com/blog/2111-issue-and-pull-request-templates

Review URL: https://codereview.appspot.com/336540043

fujiwarat/ibus,fujiwarat/ibus,fujiwarat/ibus,ibus/ibus,ibus/ibus,fujiwarat/ibus,ibus/ibus,ibus/ibus