Seems like there was a typo in the `PATH` declaration for installed
ruby gem binaries. This causes installed gems to be found.
This commit fixes it by reusing the `GEM_HOME` var so `PATH`
will use `.gems` (not `gems`) as well.
Splits docs to use three different `permalink` paths:
- `/raw/`
- `/draft/`
- `/stable/`
Otherwise docs like these clash and only one is accessible:
```
docs/draft/3-whisper-usage.md
docs/stable/3-whisper-usage.md
```
```
docs/draft/6-payloads.md
docs/stable/6-payloads.md
```
Signed-off-by: Jakub Sokołowski <jakub@status.im>