title: Column names in each table must be unique. Column name 'Prefix' in table 'dbo.AspNetUsers' is specified more than once
body: <p>I'm getting this error message every time I try and update the database.  It's very strange since when I look at my table in the migration it's only there once.  </p>
  
  <pre><code>CreateTable(
              "dbo.AspNetUsers",
              c =&gt; new
              {
                  Id = c.String(nullable: false, maxLength: 128),
                  Prefix = c.String(nullable:true),
                  FirstName = c.String(nullable:false,maxLength:250),
                  LastName = c.String(nullable:false,maxLength:250),
                  Suffix = c.String(nullable: true),
                  Email = c.String(maxLength: 250),
                  EmailConfirmed = c.Boolean(nullable: false),
                  PasswordHash = c.String(),
                  SecurityStamp = c.String(),
                  PhoneNumber = c.String(),
                  PhoneNumberConfirmed = c.Boolean(nullable: false),
                  TwoFactorEnabled = c.Boolean(nullable: false),
                  LockoutEndDateUtc = c.DateTime(),
                  LockoutEnabled = c.Boolean(nullable: false),
                  AccessFailedCount = c.Int(nullable: false),
                  UserName = c.String(nullable: false, maxLength: 256),
              })
              .PrimaryKey(t =&gt; t.Id)
              .Index(t =&gt; t.UserName, unique: true, name: "UserNameIndex");
  </code></pre>
  
  <p>If you have any ideas please let me know.</p>
  
  <p>Thanks in advance.</p>