bumped version to: 3.0.0-beta
Merge pull request #328 from xliiv/bumped-version

bumped version to: 3.0.0-beta
fixed manifest file
Merge pull request #331 from xliiv/fixed-manifest

fixed manifest file
Tenants collect plugin do not collect any data

- Rename args passed to functions from 'tenant' to 'ralph_tenant'
- Fix saving daily_tenant_info and migration