How to put post Markdown file into asset folder?

## Environment Info

Node version(`node -v`): `v10.9.0` This doesn't matter.

Your site `_config.yml` (Optional): I will describe it later.

Your theme `_config.yml` (Optional): This doesn't matter.

Hexo and Plugin version(`npm ls --depth 0`):

```
hexo-site@0.0.0 /home/alynx/stackharbor.alynx.xyz
├── hexo@3.7.1
├── hexo-blog-encrypt@2.0.7
├── hexo-deployer-git@0.3.1
├── hexo-deployer-heroku@0.1.2
├── hexo-deployer-rsync@0.1.3
├── hexo-generator-archive@0.1.5
├── hexo-generator-category@0.1.3
├── hexo-generator-feed@1.2.2
├── hexo-generator-index@0.2.1
├── hexo-generator-search@2.2.5
├── hexo-generator-sitemap@1.2.0
├── hexo-generator-tag@0.2.0
├── hexo-neat@1.0.4
├── hexo-renderer-ejs@0.3.1
├── hexo-renderer-marked@0.3.2
├── hexo-renderer-njucks@1.0.0
├── hexo-renderer-stylus@0.3.3
└── hexo-server@0.2.2
```

## For question

We all know that by default when Hexo create a post with asset folder, it creates a `:title.md` file and a `:title/` folder in `_posts/`, and in generating your `:title.md` file will be moved to `:title/index.html`.

However, this is **REALLY REALLY** anti-human and anti-editor. Because Hexo changes route while generating (your post `.md` `source` path is **NOT** `public` path), all editor cannot find the image link or other asset link, and none of them can read Hexo's `{% asset_img %}` tag.

Normal config:

```yaml
new_post_name: :title.md
post_asset_folder: true
```

Current Hexo post dir structure:

```
_posts/
|
- Some-Title.md
|
- Some-Title/
|
- Assets of Some-Title
```

If we can make it the same, I mean, the path in `source` dir will be the same in `public` dir, like your Markdown file will be put as `:title/index.md` and your asset folder is just the `:title/`, it will be better in all conditions. I think other staticf generator except Hexo uses this better way.

Better structure:

```
_posts/
|
- Some-Title/
|
- index.md (Markdown file of this post)
|
- Assets of Some-Title
```

I have tried change config to do this. First I set my config like this:

```yaml
new_post_name: :title/index.md
post_asset_folder: true
```

But it causes this:

```
_posts/
|
- Some-Title/
|
- index.md (Markdown file of this post)
|
- index/ (Hexo make another silly asset folder!)
|
- Assets of Some-Title
```

And then I changed this:

```yaml
post_asset_folder: false
```

It ignored asset file like this:

```
_posts/
|
- Some-Title/
|
- index.md (Markdown file of this post)
|
- Assets of Some-Title was IGNORED!!!
```

## For feature request

I think there is a historical reason for Hexo to use such a bad way to deal it, and we should make it better. In face I think if we keep behavior right now but generate not only post Markdown files but also other files together with this Markdown file, we can make it better by just set existing config like:

```yaml
new_post_name: :title/index.md
post_asset_folder: false
```

And get a structure like:

```
_posts/
|
- Some-Title/
|
- index.md (Markdown file of this post)
|
- DO NOT ignore Assets of Some-Title here
```

It will be better.

PS: I can use English to express my thought in most cases of coding, but a complex issue like this is hard to describe, so if there are developers speaking Chinese well we can communicate in Chinese and then translate into English to make it clearly. Thank you.