added Http backend
added Http backend

Signed-off-by: unicefinnovation <0650239e34aa7009ad6f563abe6dad0ce88c321c@unicef.org>
peterayeni/rapidsms,unicefuganda/edtrac,unicefuganda/edtrac,eHealthAfrica/rapidsms,dimagi/rapidsms-core-dev,lsgunth/rapidsms,catalpainternational/rapidsms,catalpainternational/rapidsms,unicefuganda/edtrac,caktus/rapidsms,dimagi/rapidsms,ken-muturi/rapidsms,ken-muturi/rapidsms,lsgunth/rapidsms,peterayeni/rapidsms,eHealthAfrica/rapidsms,catalpainternational/rapidsms,dimagi/rapidsms-core-dev,peterayeni/rapidsms,caktus/rapidsms,peterayeni/rapidsms,lsgunth/rapidsms,dimagi/rapidsms,catalpainternational/rapidsms,rapidsms/rapidsms-core-dev,ehealthafrica-ci/rapidsms,rapidsms/rapidsms-core-dev,ehealthafrica-ci/rapidsms,lsgunth/rapidsms,caktus/rapidsms,ken-muturi/rapidsms,eHealthAfrica/rapidsms,ehealthafrica-ci/rapidsms