moonridge.js
function regNewModel (name, schema, opts) {
  var model = MRModel.apply(moonridgeSingleton, arguments)
  models[name] = model
  return model
}
function regNewModel (name, schema, opts) {
  var model = MRModel.apply(moonridgeSingleton, arguments)
  models[name] = model
  return model
}
@param {String} name
@param {Object} schema
@param {Object} opts
@param {Function} [opts.checkPermission] function which should return true/false depending if the connected socket has/hasn't priviliges
@param {Object} [opts.permissions] with 4 properties: 'C', 'R','U', 'D' which each represents one type of operation,
values should be numbers indicating which level of privilige is needed

@returns {MRModel}