initContext = currentContext => {
  let context;

  if (currentContext) {
    context = { ...currentContext };
  } else {
    context = {};
  }

  // add all collections to context
  Collections.forEach(c => (context[c.collectionName] = c));

  // merge with custom context
  // TODO: deepmerge created an infinite loop here
  context = _merge({}, context, GraphQLSchema.context);
  return context;
}
Called once on server creation
@param {*} currentContext