Add a CONTRIBUTING.md guide

[ju-sh]

Let's add instructions to guide contributors.

Like specifying the tools and coding style to be used while making contributions.

[filyp]

I added some guidelines. There's not much of them. If you have some ideas for more of them, let me know.

[ju-sh]

How about adding a CI/CD pipeline? We can start there and decide on what other tools to use from there.

A mechanism to test the code before merging pull requests would be nice.

[filyp]

I'll try to set that up after my exams, when I have more time.

[sebincic]

hi, i need to add word to spanish's language. How can i do that? good job

[ju-sh]

@sebincic I'm not sure, but looks like it has something to do with the link here.

[filyp]

@ju-sh yeah, this file defines the location where the dictionaries are stored @sebincic right now, we don't have a mechanism for adding a single word, we gather the words by processing wikipedia (see here), so I assumed there will be no need to append more words (wikipedia is huge). Maybe your word isn't found, because we cut out the rarely used words, to improve autocorrection (see here). I wouldn't like to have a mechanism for adding single words to the main repo, because it's too much hassle, and for the reasons in the last link. But I can readd those rare words we cut out, if that would help you. Which word is it? Also, for the future, when you have a new issue, start a new github issue, not use some existing one ;)

[filyp]

I decided that setting up this CI/CD pipeline is an overkill, because contributions are really rare, so I don't think it's worth it. Maybe in the future, if this repo gets more alive I'll set something up.

[filyp]

@ju-sh I got some new traffic in this repo, so I followed your suggestion and set up automatic tests and linting here: https://github.com/fsondej/autocorrect/blob/master/.github/workflows/python-app.yml