c# - How to add foreign key in AspNetUser Asp.net MVC -

i searched answer 2 days , still did not find easy step-by-step answer question.

as can see, point need have connection between 'boeking' , 'aspnetuser'. 1 aspnetuser can have multiple 'boeking'.

this screenshot of mssql: enter image description here

what should write, in place have connection? thank sincerely taking time , effort me.

this boeking class:

public partial class boeking {     [system.diagnostics.codeanalysis.suppressmessage("microsoft.usage", "ca2214:donotcalloverridablemethodsinconstructors")]     public boeking()     {         this.hotelboekings = new hashset<hotelboeking>();         this.tickets = new hashset<ticket>();     }      public string netuserid { get; set; }     public int boekingid { get; set; }     public int trajectid { get; set; }     public system.datetime datumboeking { get; set; }     public system.datetime vertrekdatum { get; set; }     public int reservatienr { get; set; }      public virtual traject traject { get; set; }     [system.diagnostics.codeanalysis.suppressmessage("microsoft.usage", "ca2227:collectionpropertiesshouldbereadonly")]     public virtual icollection<hotelboeking> hotelboekings { get; set; }     [system.diagnostics.codeanalysis.suppressmessage("microsoft.usage", "ca2227:collectionpropertiesshouldbereadonly")]     public virtual icollection<ticket> tickets { get; set; } }