Add likes model, controller and tests

spec/factories/likes.rb

@@ -0,0 +1,6 @@
+FactoryBot.define do
+  factory :like do
+    user
+    post
+  end
+end

spec/models/like_spec.rb

@@ -0,0 +1,19 @@
+require 'rails_helper'
+
+RSpec.describe Like, type: :model do
+  let(:like) { FactoryBot.build(:like) }
+
+  it 'is valid' do
+    expect(like).to be_valid
+  end
+
+  it 'must have a user_id' do
+    like.user = nil
+    expect(like).to be_invalid
+  end
+
+  it 'must have a post_id' do
+    like.post = nil
+    expect(like).to be_invalid
+  end
+end

spec/routing/likes_routing_spec.rb

@@ -0,0 +1,18 @@
+require 'rails_helper'
+
+RSpec.describe 'likes routing', :aggregate_failures, type: :routing do
+  it 'routes likes' do
+    expect(post: '/posts/1/likes').to route_to(
+      controller: 'likes', action: 'create', post_id: "1"
+    )
+    expect(delete: '/posts/1/likes').to route_to(
+      controller: 'likes', action: 'destroy', post_id: "1"
+    )
+
+    expect(get: '/posts/1/likes').not_to be_routable
+    expect(get: '/posts/1/likes/1').not_to be_routable
+    expect(get: '/posts/1/likes/new').not_to be_routable
+    expect(get: '/posts/1/likes/1/edit').not_to be_routable
+    expect(patch: '/posts/1/likes/1').not_to be_routable
+  end
+end