add help to tasks to show some descriptions about each task
Merge pull request #57 from salimane/pr_tasks_help

add help to tasks to show some descriptions about each task
move db_dir and log_dir variables to config file together with migrations_dir, trigger error when not available
Merge pull request #58 from salimane/pr_log_db_dir_config

move db_dir and log_dir variables to config file together with migration_dir
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  move db_dir and log_dir variables to config file together with migrations_dir, trigger error when not available
  add help to tasks to show some descriptions about each task