New option to also (or only) backup database schema

Sometimes you only (or also) need to backup the schema of the database (when the data is not critical) or maybe when you exclude tables or databases from backup but you want to have their schema. I suggest that two options should be included to fulfill this objective: --tables-schema and --schema. The former to backup only the schema of the tables selected, somehow like --tables-file option does, and the later to backup all the schema of all databases. Maybe --database-schema too, to backup only the schema of specific databases.