add is_following field on user endpoint

app/models/user.rb

@@ -14,4 +14,8 @@ class User < ApplicationRecord
   has_many :user_follows_followers, class_name: 'UserFollow', foreign_key: :followed_id
   has_many :following, through: :user_follows_following, source: :followed
   has_many :followers, through: :user_follows_followers, source: :follower
+
+  def is_following?(user)
+    user_follows_following.where(followed_id: user&.id).exists?
+  end
 end

app/views/users/_user.json.jbuilder

@@ -3,5 +3,6 @@ json.joined_at user.created_at.strftime("%B %d, %Y")
 json.following_count user.following.count
 json.follower_count user.followers.count
 json.posts_count user.posts.count
+json.is_following user.is_following?(@current_user)
 
 json.url user_url(user, format: :json)

spec/models/user_spec.rb

@@ -61,4 +61,21 @@ RSpec.describe User, type: :model do
       end
     end
   end
+
+  describe '#is_following?' do
+    it do
+      following_user = create(:user)
+      now_following_user = create(:user)
+      followed_user = create(:user)
+
+      create(:user_follow, follower_id: following_user.id, followed_id: followed_user.id)
+
+      expect(
+        following_user.is_following?(followed_user)
+      ).to be_truthy
+      expect(
+        now_following_user.is_following?(followed_user)
+      ).to be_falsey
+    end
+  end
 end