Support for multiple accounts?

The more we know about your system and use case, the more easily and likely we can help.

#### Environment info
* OS: macOS 10.13.6
* App Version (`Command/Ctrl + ,`): 1.9.1

#### Description of the problem / feature request / question:

I have two Github accounts, a personal account and a work account. Both accounts have gists that I would like to view/edit with Lepton.

Is there a way for Lepton to support multiple accounts at the same time, i.e. without logging out and logging in again every time I want to work on a gist in the other account?

I would be okay with running multiple instances of Lepton using ``open -n`` as a workaround. However, if I ran it that way, the data directory will have to be different from the default for one of them.

#### If possible, provide a sample gist or screenshot:

#### If possible, provide the log files
For Lepton after v1.9.0, the path of the log file can be found at `Command/Ctrl + ,`
- Mac: `~/Library/Application Support/Lepton/logs`
- Windows: `C:\Users\\AppData\Roaming\Lepton\logs`
- Linux: `~/.cached/Lepton/logs`
>The [debug mode](https://github.com/hackjutsu/Lepton/wiki) is recommended when producing the logs.
>You can send your log file to cosmo.lepton@gmail.com if don't want to post it here.