NGitLab - how to initialise empty repository and create branches

Hi there, I’m using NGitLab to create repository. Ideally we want to use NGitLab to initialise the empty repository and create origin/master and develop branches. Problem is that I couldn’t find any api to perform “git init” or similar on the empty repository. I’ve tried using branches api (https://github.com/gitlabhq/gitlabhq/blob/master/doc/api/branches.md#create-repository-branch) to create branch in empty repository, API returned 201(created) however response appeared to be null and the repository is still empty when doing a local git clone afterwards. Help please?