我无意间创建了一个不需要的迁移，所以我删除了文件，并在尝试运行rake db：migrate时创建了一个新的迁移，但我一直收到此错误。我正在使用SQlite3 gem和Ruby on Rails 4
StandardError: An error has occurred, this and all later migrations canceled:
SQLite3::SQLException: table "categories" already exists: CREATE TABLE "categories" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "category_name" varchar, "created_at" datetime NOT NULL, "updated_at" datetime NO
T NULL) D:/muse/db/migrate/20150830113519_create_categories.rb:3:in `change'
D:in `migrate'
ActiveRecord::StatementInvalid: SQLite3::SQLException: table "categories" already exists: CREATE TABLE "categories" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "category_name" varchar, "created_at" datetime NO
T NULL, "updated_at" datetime NOT NULL)
D:/muse/db/migrate/20150830113519_create_categories.rb:3:in `change'
D:in `migrate'
SQLite3::SQLException: table …