Feature db migration

[sampsonye]

Which changes (Bug/Feature):

Fixes #55

Special notes for reviewers:

支持在代码层级进行db migrate
使用步骤：
1. 在internal/migrations中新增go文件
2. 创建Migration{datetime} 结构，并实现Migration接口的两个方法GetCreateAt、Upgrade
3. Upgrade方法写入当前文件创建的时间
4. Upgrade写入需要执行的SQL
5. 在internal/models的models.go的initMigration方法中添加自己的Migration实现

Tips：
根据时间标记升序执行，并将当次版本中时间标记最大的值记入数据库，重复启动应用，升级脚本不会重复执行

[colynn]

我们期望的应该是 引入 migrate工具，对于每次的变更项有migrate工具来解决，不然每次变更还是需要新增migrate的代码，
类似这种 https://github.com/goharbor/harbor/blob/main/src/migration/migration.go

[sampsonye]

我们期望的应该是 引入 migrate工具，对于每次的变更项有migrate工具来解决，不然每次变更还是需要新增migrate的代码，
类似这种 https://github.com/goharbor/harbor/blob/main/src/migration/migration.go

开了个讨论帖，一起讨论讨论吧：#99

[codecov-commenter]

Codecov Report

Merging #96 (71e24f1) into v1.5.0-feat-app-refactor (5314348) will not change coverage.
The diff coverage is n/a.

@@                   Coverage Diff                    @@
##           v1.5.0-feat-app-refactor     #96   +/-   ##
========================================================
  Coverage                      4.67%   4.67%           
========================================================
  Files                            10      10           
  Lines                          1454    1454           
========================================================
  Hits                             68      68           
  Misses                         1384    1384           
  Partials                          2       2           

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[colynn]

thanks sampsonye

[fanhousanbu]

LGTM

[fanhousanbu]

不考虑加个索引什么的？

[fanhousanbu]

记录来自 @sampsonye 的私下回复

https://dev.mysql.com/doc/refman/8.0/en/mysql-indexes.html

Indexes are less important for queries on small tables, or big tables where report queries process most or all of the rows. When a query needs to access most of the rows, reading sequentially is faster than working through an index. Sequential reads minimize disk seeks, even if not all the rows are needed for the query. See [Section 8.2.1.23, “Avoiding Full Table Scans”](https://dev.mysql.com/doc/refman/8.0/en/table-scan-avoidance.html) for details.

[fanhousanbu]

LGTM

[colynn]

/LGTM