Add a WFS action to the state.
@param {Object} state Current state.
@param {Object} action Action to handle.

@returns {Object} The new state.
function addAction(state, action) {
  const action_id = uuid.v4();

  const new_action = {};
  new_action[action_id] = action;

  const new_actions = Object.assign({}, state.actions, new_action);
  return Object.assign({}, state, {actions: new_actions});
}