Stubs in the start for a Group class, which represents a range of segments in the corpus.
When instantiating a Corpus reader, makes it possible to provide integer boundaries on which segments the reader should interact with.
Don't vertically align field definitions in model classes.
Adds a 'metadata' HStore column to the document model.
When yielding bounded segments out of the corpus, check that the segment directory exists before generating the Segment instance.
Commenting.
On Document, allow the metadata field to be empty.
Gets rid of unused Document#exists method.