[FEATURE]Support PostGIS and ltree extensions to Postgres

当前的程序似乎无法支持Postgres的拓展PostGIS和ltree提供的字段，我也没有在设置选项中找到开启PostGIS、ltree支持的选项。所以我只能先在程序中备注好，导出了sql语句之后再修改数据类型，是比较麻烦的。

故希望能够添加此功能，感激不尽。

Current applications don't seem to support fields provided by Postgres extensions PostGIS and ltree, and I couldn't find an option to enable the support in the Settings. So I can only make a note in the program first, and it is troublesome to modify the data type after exporting the sql statement.

I would appreciate adding support for PostGIS.