Nit: stricter version check (!= 0 instead of > 0)

The version shouldn't be negative, so it's equivalent; but I feel that
`!= 0` better matches the intent ("only run this migration if the
database is empty").

Author: tom93

db/migrate/20200418113601_load_schema.rb

@@ -1,6 +1,6 @@
 class LoadSchema < ActiveRecord::Migration
   def up
-    if ActiveRecord::Migrator.current_version > 0
+    if ActiveRecord::Migrator.current_version != 0
       raise StandardError, "The database schema is out of date; running this migration will cause irreversible data loss!"
     end