Rename post_text to lead_comment in posts table
Revert and redo renaming 'opening' to 'leading'
Delete bad migration
Add reference to posts (children) onto user (parent)
Generate Comment model as commentable polymorphic association
Edit TODO
Create Cohortship model and controller, add self-referential association
Add indices to cohortships and comments
Add inverse cohortships to User model and define create/destroy actions
Add request methods
Comment out inverse cohort(ship)s
Add accept and reject methods and controller actions to cohortships