Why do I have problems pushing new branches to my Git repository?

As a followup to my question about unavailable branches after svn to git migration, I have a different problem: I'm unable to push new branches to my central Git repository.

$ git clone ssh://server/opt/git/our_app.git
$ cd our_app
$ git branch my-test-branch
$ git checkout my-test-branch
$ echo test > test.txt
$ git add test.txt
$ git commit test.txt -m "test commit"
[master ed81ec0] test commit
1 files changed, 1 insertions(+), 0 deletions(-)
create mode 100644 test.txt
$ git push
Everything up-to-date

So, this does not push my branch to the server. A colleague advised me to look into my .git/config, which looks like this:

[core]
    repositoryformatversion = 0
    filemode = true
    bare = false
    logallrefupdates = true
    ignorecase = true
[remote "origin"]
    fetch = +refs/heads/*:refs/remotes/origin/*
    url = ssh://server/opt/git/our_app.git
[branch "master"]
    remote = origin
    merge = refs/heads/master

I was adviced to manually add a push entry:

[remote "origin"]
    fetch = +refs/heads/*:refs/remotes/origin/*
    url = ssh://server/opt/git/our_app.git
    push = refs/heads/*:refs/heads/*

Now things looked better:

$ git push
Password: 
Counting objects: 1, done.
Delta compression using up to 1 threads.
Compressing objects: 100% (1/1), done.
Writing objects: 100% (1/1), 5 bytes, done.
Total 1 (delta 1), reused 0 (delta 0)
To ssh://server/opt/git/our_app.git
 * [new branch]      my-test-branch -> my-test-branch

While this worked, it still feels like a hack. What's the proper way to do this?