Merge branch 'release/0.1.8' into develop
Remove the need for a "tahrir.salt" config value.
Remove an old print statement.
Merge pull request #10 from fedora-infra/feature/simple-salts

Feature/simple salts
add initial alembic files, point at tahrir.db, and basic readme
Add swap file extensions to .gitignore
Make Alembic run migrations as a transaction, rolling back on OperationError. Also add a migration script to add a column.
Print repr() of OperationalError.
Add 3 more Alembic scripts to complete Tahrir model changes for now.
Merge branch 'feature/alembic' into develop
Update models to match Alembic changes.
Make created_on default values be the current datetime.
Alembic script to add created_by to invitations table.
Add invitations table created_by field to model. Fixes Tahrir #58.
Merge branch 'feature/issue-58' into develop
Make Alembic scripts properly include nullable args. (Thanks, @puiterwijk!)
Make issued_on in assertions table not nullable and set default to datetime.now.
Fix failing test (was failing on add_invitation).
Fix unicode warning thrown in tests (thanks @Qalthos!)
Add get_all_assertions and get_all_persons methods.