title: Can't use migrations in EF Core: "42P07: relation "AspNetRoles" already exists"
body: <p>I have strange issue which I can't find solution for.</p>
  
  <p>The stack is: NET Core 2, EF, PostgreSQL.
  I use .NET Core Identity with <code>User : IdentityUser</code> to extend base user model with additional fields.</p>
  
  <p>After I create first migration, drop whole database and try to <code>dotnet ef database update</code> I always get an error: <code>42P07: relation "AspNetRoles" already exists</code></p>
  
  <p>Even with this error, the database and tables are created but it makes migrations useless as it does not save applied migrations so I can't update DB with following changes...</p>
  
  <blockquote>
    <p>fail: Microsoft.EntityFrameworkCore.Database.Command[200102]
          Failed executing DbCommand (0ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
          CREATE TABLE "AspNetRoles" (
              "Id" text NOT NULL,
              "ConcurrencyStamp" text NULL,
              "Name" varchar(256) NULL,
              "NormalizedName" varchar(256) NULL,
              CONSTRAINT "PK_AspNetRoles" PRIMARY KEY ("Id")
          ); Npgsql.PostgresException (0x80004005): 42P07: relation "AspNetRoles" already exists    at
    Npgsql.NpgsqlConnector.d__148.MoveNext()
    --- End of stack trace from previous location where exception was thrown ---    at
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    at
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
    task)    at System.Runtime.CompilerServices.TaskAwaiter<code>1.GetResult() 
    at System.Runtime.CompilerServices.ValueTaskAwaiter</code>1.GetResult()<br>
    at Npgsql.NpgsqlConnector.d__147.MoveNext()</p>
  </blockquote>