title: How to add thirld column in DbModelBuilder using entityframework
body: <p>I tried to add new bool field in a table with code first approach but it's doesn't work 
  please have a that is my code which i used.</p>
  
  <pre><code> modelBuilder.Entity&lt;CollegeActivity&gt;()
              .HasMany&lt;ApplicationRole&gt;(s =&gt; s.ApplicationRoles)
              .WithMany(c =&gt; c.Activities)
              .Map(cs =&gt;
              {
                  cs.MapLeftKey("ActivityId");
                  cs.MapRightKey("RoleId");
                  cs.MapRightKey("IsInternal");
                  cs.ToTable("ActivityRoleRelationship");
              });
  </code></pre>
  
  <p>Table Name : ActivityRoleRelationship</p>
  
  <p>and this new bool column which i tried to add but it's not added </p>
  
  <pre><code>cs.MapRightKey("IsInternal");
  </code></pre>
  
  <p>Can you please help me what i'm doing wrong..</p>