I'm working in a rails project which uses SVN as central repository, but i'm working (locally) with git-svn, and I want to add a remote where i will only push master for testing purposes (i will push to Heroku).
I've read this from chapter 9.1 of Pro Git (my emphasis):
Don’t rewrite your history and try to push again, and don’t push to a parallel Git repository to collaborate with fellow Git developers at the same time. Subversion can have only a single linear history, and confusing it is very easy. If you’re working with a team, and some are using SVN and others are using Git, make sure everyone is using the SVN server to collaborate — doing so will make your life easier.
I won't be collaborating with other Git developers (everyone else is using SVN), but before setting it up, i just want to be sure if there are any associated risks in doing this, and if so, what should/could i do about it.
If it's only for pushing to a repo so that you can then checkout/build/deploy, it won't hurt. That warning you noted is stated there so that you don't start moving around doing crazy things on the repo where you work with git-svn to relate to other developers also using git-svn (plus other restrictions) because of the way that revisions are kept on git-svn.