code: function(config, aliasMap, pluginInstances) {
      var self = this;
  
      pluginInstances.forEach(function(instance) {
        if (instance.runBefore) {
          var befores = self._castArray(instance.runBefore);
          config = self._mergeAuthorProvidedOrderWithConfigOrder('before', instance.name, befores, config, aliasMap);
        }
  
        if (instance.runAfter) {
          var afters = self._castArray(instance.runAfter);
          config = self._mergeAuthorProvidedOrderWithConfigOrder('after', instance.name, afters, config, aliasMap);
        }
      });
  
      var aliases = this._flattenAliasMap(aliasMap);
  
      var configNames = Object.keys(config).reduce(function(arr, key) {
        arr.push(key);
  
        var befores = self._castArray(config[key].before);
        var afters = self._castArray(config[key].after);
  
        return arr.concat(befores).concat(afters);
      }, [])
      .reduce(function(arr, key) {
        if (arr.indexOf(key) === -1) {
          arr.push(key);
        }
        return arr;
      }, []);
  
      var unknownConfigKeys = _.difference(configNames, aliases);
  
      if (unknownConfigKeys.length) {
        this._logUnknownPlugins(unknownConfigKeys, 'config.pipeline.runOrder');
      }
  
      return config;
    }
docs: Build up a hash of plugin instance execution order overrides.
  This hash will only container an entry for instances that should run in a particular order. All other instances will be ordered by their natural
  ordering.
  
  Ordering of plugin instances can be specified by users of ember-cli-deploy via `config.pipeline.runOrder` and by plugin authors via `run{Before,After}`.
  This function will attempt to merge the author defined run orders with the user defined ones.
  
  Example return value:
  
  {
  foo: { before: ['bar'] },
  baz: { after: ['boo', 'bom'] }
  }