Added migration, model and requireds.

app/core.rb

@@ -4,5 +4,6 @@
 Bundler.require
 
 app_base = "#{File.dirname(File.expand_path(__FILE__))}/.."
+Dir.glob("#{app_base}/app/api/**/*.rb").each { |i| require i }
 Dir.glob("#{app_base}/app/models/**/*.rb").each { |i| require i }
-Dir.glob("#{app_base}/app/lib/**/*.rb").each { |i| require i }
+

app/models/note.rb

@@ -0,0 +1,3 @@
+class Note < ActiveRecord::Base
+  validates :author, :title, :body, presence: true
+end

config.ru

@@ -3,7 +3,6 @@ require 'rubygems'
 require 'bundler/setup'
 require 'grape'
 require './app/core'
-require './app/api/notes'
 
 use ActiveRecord::ConnectionAdapters::ConnectionManagement
 

db/migrate/20151124152422_create_table_notes.rb

@@ -0,0 +1,15 @@
+class CreateTableNotes < ActiveRecord::Migration
+  def change
+    create_table :notes do |t|
+      t.string :author
+      t.string :title
+      t.text :content
+      t.text :summary
+      t.boolean :private, default: false
+      t.integer :valuation
+
+      t.timestamps null: false
+    end
+    add_index :notes, :author
+  end
+end

db/schema.rb

@@ -0,0 +1,29 @@
+# encoding: UTF-8
+# This file is auto-generated from the current state of the database. Instead
+# of editing this file, please use the migrations feature of Active Record to
+# incrementally modify your database, and then regenerate this schema definition.
+#
+# Note that this schema.rb definition is the authoritative source for your
+# database schema. If you need to create the application database on another
+# system, you should be using db:schema:load, not running all the migrations
+# from scratch. The latter is a flawed and unsustainable approach (the more migrations
+# you'll amass, the slower it'll run and the greater likelihood for issues).
+#
+# It's strongly recommended that you check this file into your version control system.
+
+ActiveRecord::Schema.define(version: 20151124152422) do
+
+  create_table "notes", force: :cascade do |t|
+    t.string   "author",     limit: 255
+    t.string   "title",      limit: 255
+    t.text     "content",    limit: 65535
+    t.text     "summary",    limit: 65535
+    t.boolean  "private",                  default: false
+    t.integer  "valuation",  limit: 4
+    t.datetime "created_at",                               null: false
+    t.datetime "updated_at",                               null: false
+  end
+
+  add_index "notes", ["author"], name: "index_notes_on_author", using: :btree
+
+end