Add API token to Group

app/models/group.rb

   #   @return [String]
   #     the name of the group. Must be unique across all groups.
 
+  has_secure_token :api_token
   has_many :members,
     dependent: :destroy
   has_many :people, through: :members

db/migrate/20181104220516_add_api_token_to_groups.rb

+class AddApiTokenToGroups < ActiveRecord::Migration[5.0]
+  def change
+    add_column :groups, :api_token, :string
+    add_index :groups, :api_token, unique: true
+  end
+end

db/migrate/20181104220610_generate_group_api_tokens.rb

+# Generate an API token for each group after adding the column.
+class GenerateGroupApiTokens < ActiveRecord::Migration[5.0]
+  def up
+    Group.all.each(&:regenerate_api_token)
+  end
+
+  # No-op
+  def down; end
+end

db/schema.rb

 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180904163645) do
+ActiveRecord::Schema.define(version: 20181104220610) do
 
   create_table "activities", force: :cascade do |t|
     t.string   "name"
     t.string   "name"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.string   "api_token"
+    t.index ["api_token"], name: "index_groups_on_api_token", unique: true
   end
 
   create_table "members", force: :cascade do |t|