Google Contacts & Calendar Integration

I have one project that is related to salon. in that project you can book appointment online. so you have to enter customer name,customer phone & customer email. i want to store this customer's info to my google contacts. as well as from my backend if i add any new customer or edit any existing customer so changes are also reflect in my google contacts. same way if i add any new customer or edit any existing customer in google contacts it should also reflect in my website. in google calendar i just fetch all events from google to my website.