restructured aggregation

src/models/material.ts

@@ -22,5 +22,7 @@ MaterialSchema.query.log = function <Q extends mongoose.DocumentQuery<any, any>>
   db.log(req, this);
   return this;
 }
+MaterialSchema.index({supplier_id: 1});
+MaterialSchema.index({group_id: 1});
 
 export default mongoose.model<any, mongoose.Model<any, any>>('material', MaterialSchema);