[Chore] Remove example_sentence column from table

[uzluisf]

Description

Remove example_sentence column from the encountered_words table since it already exists in the example_sentences table.

Related: #22

Testing

1. Rebuild Docker image.

chmod -R 777 ./ && docker compose -f ./docker-compose-dev-macos.yml build && docker compose -f ./docker-compose-dev-macos.yml up -d --force-recreate

2. Run the local server.

docker exec -ti linguacafe-webserver-dev npm run watch-poll

3. Log into LinguaCafe at http://localhost:3000/.

[simjanos-dev]

This would only work for a new empty database. It should be also removed from existing databases instead with a new migration file.

There's an example in this file: database/migrations/2022_04_20_143750_modify_daily_achivements_table.php

Laravel migration docs. Migrations are written in a very poor way, currently they cannot be rolled back. I want to rewrite them in the future, but had no time for it so far, and it will be difficult for already existing users.

Please also check if the phrases table have this column, but I don't think so. I've checked it, it does not have it.

Thank you so much for working on it!

[uzluisf]

@simjanos-dev I kinda slacked off on this one. I took a cursory look at those docs and couldn't figure out what I really needed to do (1st time hearing about schemas under version control) 😅 I'll try reading the docs again tomorrow and taking a stab at it.

[simjanos-dev]

Removed the column from the database.

But I appreciate your help! Feel free to open further PR-s if you would like to.

Hope you are enjoying linguacafe! :)