Corrected range() call in quickstart-python.rst

In quickstart-python.rst, the comment says "generate 10 users, with user ids 1,2,....,10" but the code actually generates 50 users. Here's a fix to the code, assuming the comment was correct.
Merge pull request #4 from adrianholovaty/patch-1

Corrected range() call in quickstart-python.rst
Add pio_rate in api doc
Add Ruby quickstart guide
Add Vagrant synced folder doc
Bump version to 0.6.4
Merge branch 'develop'