code: function simple_setters (setters) {
          // loop over the setter keys and make a mutation for each
          return Object.keys(setters).reduce(function (mutations, name) {
  
              // attach our new mutation to result
              return Object.assign({}, mutations, defineProperty({}, name, function (state, value) {
  
                  // if the setter name has a dot, then resolve the
                  // state path before feeding our value into it.
                  if (setters[name].indexOf('.') > -1) {
                      var obj = setters[name].split('.');
                      var key = obj.pop();
  
                      resolveObjectPath(state, obj)[key] = value;
                  }
  
                  // otherwise, just set the state to our value
                  else state[setters[name]] = value;
              }));
          }, {});
      }
docs: Simple mutations that set a piece of state equal to a value.
  
  @param  {Object} setters     Object mapping mutations to state
  @return {Object}