create migration readme

+# Migration `20200424124259-init`
+
+This migration has been generated by sdy at 4/24/2020, 12:42:59 PM.
+You can check out the [state of the schema](./schema.prisma) after the migration.
+
+## Database Steps
+
+```sql
+CREATE TABLE `chat_schema`.`User` (
+    `avatarUrl` varchar(191)   ,
+    `bio` varchar(191)   ,
+    `createdAt` datetime  DEFAULT CURRENT_TIMESTAMP ,
+    `email` varchar(191) NOT NULL  ,
+    `emailSecret` varchar(191)   ,
+    `id` int NOT NULL  AUTO_INCREMENT,
+    `name` varchar(191) NOT NULL  ,
+    `password` varchar(191) NOT NULL  ,
+    `phoneNumber` int   ,
+    `phoneSecret` varchar(191)   ,
+    PRIMARY KEY (`id`)
+) 
+DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
+
+CREATE TABLE `chat_schema`.`Room` (
+    `id` int NOT NULL  AUTO_INCREMENT,
+    PRIMARY KEY (`id`)
+) 
+DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
+
+CREATE TABLE `chat_schema`.`Category` (
+    `id` int NOT NULL  AUTO_INCREMENT,
+    `name` varchar(191)  DEFAULT '' ,
+    PRIMARY KEY (`id`)
+) 
+DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
+
+CREATE TABLE `chat_schema`.`Message` (
+    `id` int NOT NULL  AUTO_INCREMENT,
+    `senderId` int NOT NULL ,
+    `text` varchar(191)  DEFAULT '' ,
+    PRIMARY KEY (`id`)
+) 
+DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
+
+CREATE TABLE `chat_schema`.`_RoomToUser` (
+    `A` int NOT NULL ,
+    `B` int NOT NULL 
+) 
+DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
+
+CREATE TABLE `chat_schema`.`_CategoryToRoom` (
+    `A` int NOT NULL ,
+    `B` int NOT NULL 
+) 
+DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
+
+CREATE UNIQUE INDEX `User.email` ON `chat_schema`.`User`(`email`)
+
+CREATE UNIQUE INDEX `_RoomToUser_AB_unique` ON `chat_schema`.`_RoomToUser`(`A`,`B`)
+
+CREATE  INDEX `_RoomToUser_B_index` ON `chat_schema`.`_RoomToUser`(`B`)
+
+CREATE UNIQUE INDEX `_CategoryToRoom_AB_unique` ON `chat_schema`.`_CategoryToRoom`(`A`,`B`)
+
+CREATE  INDEX `_CategoryToRoom_B_index` ON `chat_schema`.`_CategoryToRoom`(`B`)
+
+ALTER TABLE `chat_schema`.`Message` ADD FOREIGN KEY (`senderId`) REFERENCES `chat_schema`.`User`(`id`) ON DELETE CASCADE ON UPDATE CASCADE
+
+ALTER TABLE `chat_schema`.`_RoomToUser` ADD FOREIGN KEY (`A`) REFERENCES `chat_schema`.`Room`(`id`) ON DELETE CASCADE ON UPDATE CASCADE
+
+ALTER TABLE `chat_schema`.`_RoomToUser` ADD FOREIGN KEY (`B`) REFERENCES `chat_schema`.`User`(`id`) ON DELETE CASCADE ON UPDATE CASCADE
+
+ALTER TABLE `chat_schema`.`_CategoryToRoom` ADD FOREIGN KEY (`A`) REFERENCES `chat_schema`.`Category`(`id`) ON DELETE CASCADE ON UPDATE CASCADE
+
+ALTER TABLE `chat_schema`.`_CategoryToRoom` ADD FOREIGN KEY (`B`) REFERENCES `chat_schema`.`Room`(`id`) ON DELETE CASCADE ON UPDATE CASCADE
+
+DROP TABLE `chat_schema`.`_categorytoroom`;
+
+DROP TABLE `chat_schema`.`_migration`;
+
+DROP TABLE `chat_schema`.`_roomtouser`;
+
+DROP TABLE `chat_schema`.`category`;
+
+DROP TABLE `chat_schema`.`message`;
+
+DROP TABLE `chat_schema`.`room`;
+
+DROP TABLE `chat_schema`.`test`;
+
+DROP TABLE `chat_schema`.`user`;
+```
+
+## Changes
+
+```diff
+diff --git schema.prisma schema.prisma
+migration 20200419160117-init..20200424124259-init
+--- datamodel.dml
++++ datamodel.dml
+@@ -4,18 +4,20 @@
+ }
+ datasource db {
+   provider = "mysql"
+-  url = "***"
++  url      = env("DATABASE_URL")
+ }
+ model User {
+   id          Int       @default(autoincrement()) @id
+   avatarUrl   String?
+   email       String    @unique
+   password    String
+   name        String
+-  loginSecret String?
++  phoneNumber Int?
++  emailSecret String?
++  phoneSecret String?
+   bio         String?
+   rooms       Room[]    @relation(references: [id])
+   messages    Message[]
+   createdAt   DateTime? @default(now())
+```
+
+