Merge pull request #3 from gyermich/galina

added tasks
user_task table, added relationships
models for task_category, user_category, category, relationships
Merge pull request #4 from gyermich/asha

user_task table, added relationships
Merge pull request #5 from gyermich/galina

added bootstrap
controller methods for categories, tasks, users
Merge pull request #6 from gyermich/asha

controller methods for categories, tasks, users
added session controller