A lot of git and git-buildpackage commands needed got more than one option, are needed seldom and are hard to remember. This page is supposed to be a reminder, not a detailed explanation. Like: You remember you had to use a git-buildpackage command, but can't find it in your notes any more (and neither online).
clone from gitorious for rebuilding
gbp-clone --pristine-tar email@example.com:debian-diaspora/ruby-columnize.git
By cloning like this you will be able to build the package with
for example if you want to have a look at the package of someone else.
import new upstream version
If there is a working debian/watch file:
git-import-orig --pristine-tar --uscan
If you need to download a new upstream tarball manually:
git-import-orig --pristine-tar path/to/<new-upstream-version>.tar.gz
To push to gitorious run
git push --all git push --tags
A typical gotcha is to "git push origin master" instead (and or to forget the --tags push).