Update permalink suffix generation with SecureRandom
Fix permalinks with numbers that start with zero

The problem is with Integer('0457') that raises an error and do not add
the klass prefix. The prefix is needed to not be confused with the id.
Merge pull request #6 from teambox/fix/numeric-values-starting-with-zero

Fix/numeric values starting with zero
Merge pull request #5 from teambox/use-secure-random

Update permalink suffix generation with SecureRandom