This will be used to download data from [NCBI](https://www.ncbi.nlm.nih.gov/) into Candis. **Checklist:** to implement - [x] Add API endpoint to call Entrez module. - [x] Add GEO module - [x] Implement Esearch - [x] Implement Esummary - [x] Implement the logic as described in https://www.ncbi.nlm.nih.gov/geo/info/geo_paccess.html#ExampleIII - [x] Use socket.io for download progress. - [ ] Add test cases - [x] Remove time.sleep() - [x] Setup logging instead of print statements. - refer #137 - [x] Start redis server from ~Procfile~ (now using honho Manager class) - use different port if initialized. - refer #99 - [ ] ftplib is used for downloading- show progress bar (It shows up with 'wget') - [x] Integrate with front-end. - refer issue #110 **TODO**: Improvements needed as mentioned in the related PRs to #110 - [ ] Add JS test cases for the same. - [ ] Instead of using requests.Timeout error, use custom error class.