Basic storage

>>> from woger import WorkspaceStorage, BasePathStructure, Workspace
>>>
>>> storage = WorkspaceStorage()
>>>
>>> print(len(storage))
0
>>>
>>> ws = Workspace.construct('257', BasePathStructure)
>>> storage.add(ws)
>>>
>>> print(len(storage))
1
>>> ws = Workspace.construct('175', BasePathStructure)
>>> storage.add(ws)
>>>
>>> print(len(storage))
2
>>> print(storage)
<WorkspaceStorage [175, 257]>