Hi, Recently, our laboratory want to connect Gitlab with Jira. We have installed Gitlab CE and Jira6.0.1.
We have connected Jira successfully. But when I tried to create issue on Gitlab, it just redirected to Jira simply. I think the reason is that our Gitlab is CE version. We should install GitLab EE.
I have read some documents about Gitlab integrating Jira. It said we can do the following things:(http://doc.gitlab.com/ee/integration/jira.html#configuration)
(1)Referencing Jira Issues from GitLab
(2)Closing Jira Issues from GitLab
If we installed GitLab EE, we can do the two listing things above, right? But I did not know the mechanism, So I have two questiongs:
(1) Does Gitlab invoke Jira APIs to get and post data?
(2) I know Gitlab provide APIs, If I create an issue through invoking GitLab API, I am sure that there will be a new issue in GitLab. Will be a new issue in Jira too?
Invoking GitLab API to create an issue —> A new issue in GitLab --??–> A new issue in Jira?
Thanks!! 
