 Bielefeld location 2018 added sponsors (#308)
 Bielefeld location 2018 added sponsors (#308)

* Bielefeld location 2018 added

* Bielefeld location 2018 added sponsors

coderetreat/coderetreat.github.io,coderetreat/coderetreat.github.io,svenlange/coderetreat.github.io,coderetreat/coderetreat.github.io,svenlange/coderetreat.github.io,svenlange/coderetreat.github.io,yugangbai/coderetreat.github.io,coderetreat/coderetreat.github.io,yugangbai/coderetreat.github.io,yugangbai/coderetreat.github.io,svenlange/coderetreat.github.io,yugangbai/coderetreat.github.io