Manually committed Lua code in repository breaks history

[harningt]

When looking at history, the code that maps a user identifier to a Gravatar throws due to a check that the length is zero. Somehow the 'user' value that is entering comes in as the number 1.

Given that it looks like the user identifier comes from the 'committer' that is used in git, in my example it was:

Thomas Harning Jr <[email protected]>

Perhaps a useful feature would be to permit mapping a Git committer to a specific user for purposes of history/etc. Perhaps based off of email address, full name, or both.

[yuri]

I am planning to move from the current git code to luagit2. This would be a good time to fix this, probably.