added basic sample how to use migrations

sample/sample32-migrations/app.ts

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+import "reflect-metadata";
+import {ConnectionOptions, createConnection} from "../../src/index";
+import {Post} from "./entity/Post";
+import {Author} from "./entity/Author";
+
+const options: ConnectionOptions = {
+    driver: {
+        type: "mysql",
+        host: "localhost",
+        port: 3306,
+        username: "root",
+        password: "admin",
+        database: "test"
+    },
+    autoSchemaSync: true,
+    logging: {
+        // logQueries: true,
+        // logSchemaCreation: true,
+        // logFailedQueryError: true
+    },
+    entities: [Post, Author],
+};
+
+createConnection(options).then(async connection => {
+
+    let author = new Author();
+    author.firstName = "Umed";
+    author.lastName = "Khudoiberdiev";
+
+    let post = new Post();
+    post.title = "hello";
+    post.author = author;
+
+    let postRepository = connection.getRepository(Post);
+
+    await postRepository.persist(post);
+    console.log("Post has been saved");
+
+}).catch(error => console.log("Error: ", error));

sample/sample32-migrations/entity/Author.ts

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+import {PrimaryGeneratedColumn, Column, Table} from "../../../src/index";
+
+@Table()
+export class Author {
+
+    @PrimaryGeneratedColumn()
+    id: number;
+
+    @Column()
+    firstName: string;
+
+    @Column()
+    lastName: string;
+
+}

sample/sample32-migrations/entity/Post.ts

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+import {PrimaryGeneratedColumn, Column, Table, ManyToOne} from "../../../src/index";
+import {Author} from "./Author";
+
+@Table()
+export class Post {
+
+    @PrimaryGeneratedColumn()
+    id: number;
+
+    @Column()
+    title: string;
+
+    @ManyToOne(type => Author, {
+        cascadeInsert: true
+    })
+    author: Author;
+
+}

sample/sample32-migrations/migrations/1481283582-first-release-changes.ts

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+import {MigrationInterface} from "../../../src/migration/MigrationInterface";
+import {Connection} from "../../../src/connection/Connection";
+import {QueryRunner} from "../../../src/query-runner/QueryRunner";
+
+export class FirstReleaseMigration implements MigrationInterface {
+
+    async up(queryRunner: QueryRunner, connection: Connection): Promise<any> {
+        await queryRunner.query("ALTER TABLE `post` CHANGE `title` `name` VARCHAR(255)");
+    }
+
+    async down(queryRunner: QueryRunner, connection: Connection): Promise<any> {
+        await queryRunner.query("ALTER TABLE `post` CHANGE `name` `title` VARCHAR(255)");
+    }
+
+}