Add Post model

app/models/post.rb

@@ -0,0 +1,7 @@
+class Post < ApplicationRecord
+  belongs_to :board
+  belongs_to :user
+  belongs_to :post_status, optional: true
+
+  validates :title, presence: true, length: { in: 4..64 }
+end

db/migrate/20190824141258_create_posts.rb

@@ -0,0 +1,13 @@
+class CreatePosts < ActiveRecord::Migration[6.0]
+  def change
+    create_table :posts do |t|
+      t.string :title, null: false
+      t.text :description
+      t.references :board, null: false, foreign_key: true
+      t.references :user, null: false, foreign_key: true
+      t.references :post_status, foreign_key: true
+
+      t.timestamps
+    end
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2019_08_24_093755) do
+ActiveRecord::Schema.define(version: 2019_08_24_141258) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -31,6 +31,19 @@ ActiveRecord::Schema.define(version: 2019_08_24_093755) do
     t.index ["name"], name: "index_post_statuses_on_name", unique: true
   end
 
+  create_table "posts", force: :cascade do |t|
+    t.string "title", null: false
+    t.text "description"
+    t.bigint "board_id", null: false
+    t.bigint "user_id", null: false
+    t.bigint "post_status_id"
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+    t.index ["board_id"], name: "index_posts_on_board_id"
+    t.index ["post_status_id"], name: "index_posts_on_post_status_id"
+    t.index ["user_id"], name: "index_posts_on_user_id"
+  end
+
   create_table "users", force: :cascade do |t|
     t.string "email", default: "", null: false
     t.string "encrypted_password", default: "", null: false
@@ -50,4 +63,7 @@ ActiveRecord::Schema.define(version: 2019_08_24_093755) do
     t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
 
+  add_foreign_key "posts", "boards"
+  add_foreign_key "posts", "post_statuses"
+  add_foreign_key "posts", "users"
 end

spec/factories/posts.rb

@@ -0,0 +1,9 @@
+FactoryBot.define do
+  factory :post do
+    title { "Post Title" }
+    description { "Post Description" }
+    board
+    user
+    post_status
+  end
+end

spec/models/post_spec.rb

@@ -0,0 +1,55 @@
+require 'rails_helper'
+
+RSpec.describe Post, type: :model do
+  let(:post) { FactoryBot.build(:post) }
+
+  it 'should be valid' do
+    expect(post).to be_valid
+  end
+
+  it 'has a non-null and non-empty title' do
+    nil_post = FactoryBot.build(:post, title: nil)
+    empty_post = FactoryBot.build(:post, title: "")
+
+    expect(nil_post).to be_invalid
+    expect(empty_post).to be_invalid
+  end
+
+  it 'has a title between 4 and 64 characters' do
+    too_short_post = FactoryBot.build(:post, title: "a" * 3)
+    short_post = FactoryBot.build(:post, title: "a" * 4)
+    long_post = FactoryBot.build(:post, title: "a" * 64)
+    too_long_post = FactoryBot.build(:post, title: "a" * 65)
+
+    expect(too_short_post).to be_invalid
+    expect(short_post).to be_valid
+    expect(long_post).to be_valid
+    expect(too_long_post).to be_invalid
+  end
+
+  it 'has a description that can be nil or empty' do
+    nil_description_post = FactoryBot.build(:post, description: nil)
+    empty_description_post = FactoryBot.build(:post, description: "")
+
+    expect(nil_description_post).to be_valid
+    expect(empty_description_post).to be_valid
+  end
+
+  it 'has a reference to a post status that can be nil' do
+    no_status_post = FactoryBot.build(:post, post_status_id: nil)
+    
+    expect(no_status_post).to be_valid
+  end
+
+  it 'has a reference to a user than cannot be nil' do
+    no_user_post = FactoryBot.build(:post, user_id: nil)
+
+    expect(no_user_post).to be_invalid
+  end
+
+  it 'has a reference to a board than cannot be nil' do
+    no_board_post = FactoryBot.build(:post, board_id: nil)
+
+    expect(no_board_post).to be_invalid
+  end
+end