Migration issue

php artisan migrate:

```
[Illuminate\Database\QueryException] SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes (SQL: SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes (SQL: alter table 'tracker_languages' add unique 'tracker_languages_ preference_languagerange_unique'('preference, 'language—range')))

[PDOException] SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes

```

Error persists after employing the fix given in issue [SQLSTATE[42000]: Syntax error, upon migrating on a new install.](https://github.com/antonioribeiro/tracker/issues/214)

Laravel 5.2

Start by running `php artisan migrate` on a new Laravel 5.2 install and compare the result with the fix discussed in issue 214. Inspect the migration that creates the `tracker_languages` unique key; done means the migration completes without the reported key-length error.

Written by the indexing model from the issue text.