Maybe more things to note in docs

[johnmave126]

I think maybe in docs, more database related options can be added.
Current Docs only note the following

DATABASE = {
    'name': 'example.db',
    'engine': 'peewee.SqliteDatabase',
}

Only after reading the source did I realize that I can pass more options to it.
For example, for someone who is using MySQL(need authentication)

DATABASE = {
    'name': 'test',
    'engine': 'peewee.MySQLDatabase',
    'user': 'username',
    'passwd': 'password',
}

For a multi-thread application, especially for a MySQL application, I found it important to set thread_locals to True.
So this is ok

DATABASE = {
    'name': 'test',
    'engine': 'peewee.MySQLDatabase',
    'user': 'username',
    'passwd': 'password',
    'threadlocals': True,
}

Or there is high probability to face coleifer/peewee#222 (comment)
I suggest add some tips in docs to clarify these information...