Rails with Octopus gemstone. How to create db defined in shards.yml with rake

I need to configure my application to use multiple shards and even multiple db adapters. I noticed that all rake commands, such as rake db:migrate, work and have consequences for shards defined in shards.yml, except rake db:create. It will be a real pain to create it all manually. How can I make it work?

My .yml database (I defined here, only my master shard)

development:
  adapter:  postgresql
  host:     localhost
  encoding: unicode
  database: db_workload_master_development
  pool:     5
  username: 
  password: 

production:
  ...... 

My shards.yml

octopus:
  environments:
    - production
    - development
  development:
    shards:
      mysql:
        host: localhost
        adapter: mysql2
        database: db_workload_mysql_shard_development
      sqlite:
        host: localhost
        adapter: sqlite3
        database: db_workload_sqlite_shard_development
      pg:
        host: localhost
        adapter: postgresql
        database: db_workload_pg_shard_development
        pool:     5
        username: 
        password: 
  production:
    ....

Only db from the .yml database are created using rake-task rake db:create.