Add set_request method
Do not delete unsassigned plates
Refactor specs
Set tag_id to -1 by default. Insert a new aliquot after a transfer only if it does not exist yet.
Set the study_id when creating a new aliquot. Insert a request on aliquot creation and update only if it does not exist yet
Add specs
fix specs
Bump version to 0.7.11
Merge pull request #35 from llh1/52641261_fix_samples_for_qc_reports

52641261 fix samples for qc reports