validate presence of user on gpg_key

app/models/gpg_key.rb

@@ -6,6 +6,8 @@ class GpgKey < ActiveRecord::Base
   belongs_to :user
   has_many :gpg_signatures, dependent: :nullify
 
+  validates :user, presence: true
+
   validates :key,
     presence: true,
     uniqueness: true,

spec/models/gpg_key_spec.rb

@@ -6,6 +6,7 @@ describe GpgKey do
   end
 
   describe "validation" do
+    it { is_expected.to validate_presence_of(:user) }
     it { is_expected.to validate_presence_of(:key) }
     it { is_expected.to validate_uniqueness_of(:key) }
     it { is_expected.to allow_value("-----BEGIN PGP PUBLIC KEY BLOCK-----\nkey").for(:key) }