0.6.2

• Bug - Migration 0002 and 0003 were not working properly for postgresql (maybe oracle). For these databases, data can not be fixed. Because, django migrates each in a transactional block and schema migration and data migration can not be done in a transactional block. To fix this, data fixing and schema fixing are separated.
• Improvement - Timeline section is added into documentation.
• Improvement - State slug field is set as slug version of its label if it is not given on saving.