[feature] New user sign-up via web page (#2796)

* [feature] User sign-up form and admin notifs

* add chosen + filtered languages to migration

* remove stray comment

* chosen languages schmosen schmanguages

* proper error on local account missing

internal/db/bundb/migrations/20240401130338_sign_up.go

@@ -0,0 +1,124 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package migrations
+
+import (
+	"context"
+	"strings"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/uptrace/bun"
+)
+
+func init() {
+	up := func(ctx context.Context, db *bun.DB) error {
+		// Add reason to users table.
+		_, err := db.ExecContext(ctx,
+			"ALTER TABLE ? ADD COLUMN ? TEXT",
+			bun.Ident("users"), bun.Ident("reason"),
+		)
+		if err != nil {
+			e := err.Error()
+			if !(strings.Contains(e, "already exists") ||
+				strings.Contains(e, "duplicate column name") ||
+				strings.Contains(e, "SQLSTATE 42701")) {
+				return err
+			}
+		}
+
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+			// Get reasons from
+			// account settings.
+			type idReason struct {
+				AccountID string
+				Reason    string
+			}
+
+			reasons := []idReason{}
+			if err := tx.
+				NewSelect().
+				Table("account_settings").
+				Column("account_id", "reason").
+				Scan(ctx, &reasons); err != nil {
+				return err
+			}
+
+			// Add each reason to appropriate user.
+			for _, r := range reasons {
+				if _, err := tx.
+					NewUpdate().
+					Table("users").
+					Set("? = ?", bun.Ident("reason"), r.Reason).
+					Where("? = ?", bun.Ident("account_id"), r.AccountID).
+					Exec(ctx, &reasons); err != nil {
+					return err
+				}
+			}
+
+			// Remove now-unused column
+			// from account settings.
+			if _, err := tx.
+				NewDropColumn().
+				Table("account_settings").
+				Column("reason").
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			// Remove now-unused columns from users.
+			for _, column := range []string{
+				"current_sign_in_at",
+				"current_sign_in_ip",
+				"last_sign_in_at",
+				"last_sign_in_ip",
+				"sign_in_count",
+				"chosen_languages",
+				"filtered_languages",
+			} {
+				if _, err := tx.
+					NewDropColumn().
+					Table("users").
+					Column(column).
+					Exec(ctx); err != nil {
+					return err
+				}
+			}
+
+			// Create new UsersDenied table.
+			if _, err := tx.
+				NewCreateTable().
+				Model(&gtsmodel.DeniedUser{}).
+				IfNotExists().
+				Exec(ctx); err != nil {
+				return err
+			}
+
+			return nil
+		})
+	}
+
+	down := func(ctx context.Context, db *bun.DB) error {
+		return db.RunInTx(ctx, nil, func(ctx context.Context, tx bun.Tx) error {
+			return nil
+		})
+	}
+
+	if err := Migrations.Register(up, down); err != nil {
+		panic(err)
+	}
+}