OSM groups: an initial draft of a migration

gistfile1.rb

create_table :groups do |t|
  t.string :name
  t.string :slug
  t.text :description
  t.decimal :nw_longitude
  t.decimal :nw_latitude
  t.decimal :se_longitude
  t.decimal :se_latitude
  t.integer :owner_user_id
  t.timestamps
end

create_table :group_membership do |t|
  t.integer :group_id
  t.integer :user_id
  t.timestamps
end