implement binary search tree in Go
Update rouge. Fixes #1294.
Add configuration to specific which emoji to load.

- Bump emojify-cdn to 0.0.2
Merge pull request #1296 from austenito/disable_smileys

Add configuration to specific which emoji to load.
Move migrate rake task into separate file
Add generate:migration rake task
Fix path error in rake task
Adds ability for user to share submitted exercise on twitter
Merge pull request #1295 from meaganewaller/add-sharing

Adds ability for sharing to twitter for submitted exercise
Delete vestiges of wants_opinion feature
Delete left-over stashed submissions
Sort pending submissions in ascending order.
Merge pull request #1299 from austenito/ascending_sorted_submissions

Sort pending submissions in ascending order.
Add mailing list to readme
haskell - simplify crypto-square example implementation using transpose
Merge pull request #1300 from austenito/mailing_list_readme

Add mailing list to readme
Merge pull request #1301 from etrepum/haskell-exercises

haskell - simplify crypto-square example implementation using transpose
Add nitpicking streak statistics.

This necessitates casting from timestamp to date, which PostgreSQL and
SQLite3 do differently from one another. I'll need to swap the test
database over to PostgreSQL soon so I can get proper test coverage of
this feature :/
Fix README for rna-transcription exercise
Fix small usage printout