fix deploy problems due to renamed table

lib/table_migration_helper.rb

@@ -0,0 +1,53 @@
+class TableMigrationHelper
+  def self.read_only_table(table_name)
+    ActiveRecord::Base.exec_sql <<-SQL
+    CREATE OR REPLACE FUNCTION raise_read_only() RETURNS trigger AS $rro$
+      BEGIN
+        RAISE EXCEPTION 'Table is read only';
+        RETURN null;
+      END
+    $rro$ LANGUAGE plpgsql;
+    SQL
+
+    ActiveRecord::Base.exec_sql <<-SQL
+    CREATE TRIGGER #{table_name}_read_only
+    BEFORE INSERT OR UPDATE OR DELETE OR TRUNCATE
+    ON #{table_name}
+    FOR EACH STATEMENT
+    EXECUTE PROCEDURE raise_read_only();
+    SQL
+  end
+
+  def self.delayed_drop(old_name:, new_name:, after_migration:, delay: nil, on_drop: nil)
+    delay ||= Rails.env.production? ? 300 : 0
+
+   sql = <<SQL
+    SELECT 1
+    FROM INFORMATION_SCHEMA.TABLES
+    WHERE table_schema = 'public' AND
+          table_name = :old_name AND
+          EXISTS (
+            SELECT 1
+            FROM schema_migration_details
+            WHERE name = :after_migration AND
+                  created_at <= (current_timestamp at time zone 'UTC' - interval :delay)
+          )
+          AND EXISTS (
+            SELECT 1
+            FROM INFORMATION_SCHEMA.TABLES
+            WHERE table_schema = 'public' AND
+            table_name = :new_name
+          )
+    LIMIT 1
+SQL
+
+    if ActiveRecord::Base.exec_sql(sql, old_name: old_name,
+                                        new_name: new_name,
+                                        delay: "#{delay.to_i || 0} seconds",
+                                        after_migration: after_migration).to_a.length > 0
+        on_drop&.call
+
+        ActiveRecord::Base.exec_sql("DROP TABLE #{old_name}")
+    end
+  end
+end