add "revision" column to wikipedia_works and celery will crawl articles which has larger revision than last max crawled revision
get revision first and use again
pep8
add EOL, delete useless comment, sort imports
Merge pull request #45 from miaekim/celery

Add revision feature to wikipedia_works
define Title class and add relationships of it
Test on Title, and stylistic change
add migration script for titles
adjust frontend and test on it for multiple titles
remove old migration script
resolve conflicts
define LocaleType is used as Locale in SQLAlchemy
define orm classes for multiple titles, apply them
fix error in getting canonical name in PostgreSQL