prepare db for groups
add timestamps to preferences table
updated for groups, added timestamps to prefs
reference seed file outside repo
set up associations and validations for groups
groupies -- all members of all groups
create invites table
create invite model
add invites and invited_to association
add invites and invitees associations
add groups, invites, memberships resources
move check_auth function to application controller
create index, show, create, destroy actions
set @group for use in view
change for inviting to groups instead of selecting a partner
links to My Groups and New Invitations
create index, destroy, create actions
create create and destroy actions
create form for creating a group
list groups, provide links to invite, leave, delete