Adds Microposts.organization_id
Renames Relationship.followed_id to followed_user_id
Adds Relationship.followed_organization_id and associations between User, Organization and Relationship
Updates Micropost.from_users_and_organizations_followed_by(user) feed generating method
Tests and fixes Micropost.from_users_and_organizations_followed_by(user)
Buttons for following organizations
Adds posting as organization
Small refactorings
postgresql dev and test migration