Write an Android application includes only a sych adapter and account authentication

We need an android app that contain only sync adapter including account authentication process for syncing a server contacts with the android device contact. the sync process should be bi-directional. possible actions on the contacts should be (ADD - EDIT only). The server side will be held by a sub-contract from our side. So who will take the job should decide on what services should be implemented on the REST api. The output of the rest api will be JSON messages combined with the HTTP codes. For more information please be in touch. The Connection Diagram and fields to be synced is Attached. At the end of the project the full source should be provided to us.