use ShaAttribute for gpg table columns

app/models/gpg_key.rb

 class GpgKey < ActiveRecord::Base
   KEY_PREFIX = '-----BEGIN PGP PUBLIC KEY BLOCK-----'.freeze
+  include ShaAttribute
+
+  sha_attribute :primary_keyid
+  sha_attribute :fingerprint
+
   belongs_to :user
   has_many :gpg_signatures, dependent: :nullify

app/models/gpg_signature.rb

 class GpgSignature < ActiveRecord::Base
+  include ShaAttribute
+
+  sha_attribute :commit_sha
+  sha_attribute :gpg_key_primary_keyid
+
   belongs_to :project
   belongs_to :gpg_key

app/views/profiles/gpg_keys/_key.html.haml

@@ -6,7 +6,7 @@
       = render partial: 'email_with_badge', locals: { email: email, verified: verified }
     .description
-      %code= key.fingerprint
+      %code= key.fingerprint.upcase
   .pull-right
     %span.key-created-at
       created #{time_ago_with_tooltip(key.created_at)}

app/views/projects/commit/_signature_badge.html.haml

@@ -9,7 +9,7 @@
     = content
   GPG Key ID:
-  %span.monospace= signature.gpg_key_primary_keyid
+  %span.monospace= signature.gpg_key_primary_keyid.upcase
   = link_to('Learn more about signing commits', help_page_path('workflow/gpg_signed_commits/index.md'), class: 'gpg-popover-help-link')

db/migrate/20170222111732_create_gpg_keys.rb

@@ -7,8 +7,8 @@ class CreateGpgKeys < ActiveRecord::Migration
       t.references :user, index: true, foreign_key: true
-      t.string :fingerprint
-      t.string :primary_keyid
+      t.binary :primary_keyid, limit: Gitlab::Database.mysql? ? 20 : nil
+      t.binary :fingerprint, limit: Gitlab::Database.mysql? ? 20 : nil
       t.text :key

db/migrate/20170613154149_create_gpg_signatures.rb

@@ -10,8 +10,9 @@ class CreateGpgSignatures < ActiveRecord::Migration
       t.boolean :valid_signature
-      t.string :commit_sha
-      t.string :gpg_key_primary_keyid
+      t.binary :commit_sha, limit: Gitlab::Database.mysql? ? 20 : nil
+      t.binary :gpg_key_primary_keyid, limit: Gitlab::Database.mysql? ? 20 : nil
+
       t.string :gpg_key_user_name
       t.string :gpg_key_user_email

db/migrate/limits_to_mysql.rb

@@ -8,5 +8,9 @@ class LimitsToMysql < ActiveRecord::Migration
     change_column :snippets, :content, :text, limit: 2147483647
     change_column :notes, :st_diff, :text, limit: 2147483647
     change_column :events, :data, :text, limit: 2147483647
+    change_column :gpg_keys, :primary_keyid, :binary, limit: 20
+    change_column :gpg_keys, :fingerprint, :binary, limit: 20
+    change_column :gpg_signatures, :commit_sha, :binary, limit: 20
+    change_column :gpg_signatures, :gpg_key_primary_keyid, :binary, limit: 20
   end
 end

db/schema.rb

@@ -544,8 +544,8 @@ ActiveRecord::Schema.define(version: 20170725145659) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.integer "user_id"
-    t.string "fingerprint"
-    t.string "primary_keyid"
+    t.binary "primary_keyid"
+    t.binary "fingerprint"
     t.text "key"
   end
@@ -558,8 +558,8 @@ ActiveRecord::Schema.define(version: 20170725145659) do
     t.integer "project_id"
     t.integer "gpg_key_id"
     t.boolean "valid_signature"
-    t.string "commit_sha"
-    t.string "gpg_key_primary_keyid"
+    t.binary "commit_sha"
+    t.binary "gpg_key_primary_keyid"
     t.string "gpg_key_user_name"
     t.string "gpg_key_user_email"
   end