DEV: Drop unused api_keys.key column

This completes the migration to hashed API keys which was started in 4c9ca24ccf

db/post_migrate/20191219112000_remove_key_from_api_keys.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+class RemoveKeyFromApiKeys < ActiveRecord::Migration[6.0]
+  DROPPED_COLUMNS ||= {
+    api_keys: %i{key}
+  }
+
+  def up
+    DROPPED_COLUMNS.each do |table, columns|
+      Migration::ColumnDropper.execute_drop(table, columns)
+    end
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end