Fix authentication

[CorentinB]

Apparently the cookie's name for session auth changed, it's now "_gabsocial_session".

[milesmcc]

Interestingly, it seems like maybe both are required? When I log into Gab, I see both _gabsocial_session and _session_id being set:

Is there an error you're running into? I suppose we could update this check to verify both are present.

[CorentinB]

Hi @milesmcc, I quickly talked with @lxcode about this, it looks like on my end only _gabsocial_session is used, on his, he was only seeing _session_id indeed.

I guess it's more one or the other than both at the same time. We could add a check to see if one of the two is present?

[milesmcc]

That approach makes sense to me! Want to update this PR? I can also just make the push.