hasCapability = async (capability, key) => {
    // Write keys and admins keys are allowed
    const access = new Set(await get(capability))
    return access.has(key) || access.has('*')
  }
Checks whether an identity has a capability.
@param {string} capability A capability (e.g. write).
@param {string} key An id of an identity.
@return {boolean} True if the identity has the capability, false
otherwise.
@memberof module:AccessControllers.AccessControllers-OrbitDB
@instance