Add github user id to user creations

db/migrate/20160822093606_add_github_user_id_to_user_creations.rb

@@ -0,0 +1,7 @@
+Sequel.migration do
+  change do
+    alter_table :user_creations do
+      add_column :github_user_id, :bigint
+    end
+  end
+end