add first scratch of models
fix attrs and methods of Circle
introducing CircleManager
fix timestamp attrs
methods for opening/closing circle sessions
fix typo in related_name
remove obsolete topic validators
remove obsolete Topic.save() method
move POLL_OUTCOMES to global model scope
Merge branch 'feature/participation' into develop
additional validation for formal opening/closing
open/close method now return self
introducing TopicManager()
comply to RFC; remove validation
fix Topic.applicant attribute
fix TopicManager.upcoming method
add e-mail attribute to topic
avoid duplicate collection bins
add notes for front-end devs
extend TopicManager.over method