Validate key uniqueness across Key and DeployKey tables

lib/unique_public_key_validator.rb

@@ -0,0 +1,7 @@
+class UniquePublicKeyValidator < ActiveModel::Validator
+  def validate(record)
+    if (DeployKey.where('key = ? AND id !=?', record.key , record.id).count > 0 || Key.where('key = ? AND id !=?', record.key , record.id).count > 0)
+      record.errors.add :key, 'already exist.'
+    end
+  end
+end