field unique=True doesn't work?
Call model.create_table instead. Db method just creates the table while model method creates indexes as well.
 thanks, worked great!

Running the latest branch, and the following model doesn't create what I think it does, a unique constraint on the field.

```
import peewee

db = peewee.SqliteDatabase("test.db")

class table1(peewee.Model):
    field1 = peewee.CharField(unique=True)
    field2 = peewee.CharField(null=True)

    class Meta:
        database = db   

db.create_table(table1)

(vPython27) C:\Users\jmatthew\Development\settingsmgr>sqlite3 test.db
SQLite version 3.7.17 2013-05-20 00:56:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> .sch
CREATE TABLE "table1" ("id" INTEGER NOT NULL PRIMARY KEY, "field1" VARCHAR(255) NOT NULL, "field2" V
ARCHAR(255));
sqlite>

```

Am i missing anything?  I looked in the source but didn't see anywhere that that field uniqueness was referenced while generating the table create.

Love the library, let me know how i can help

J
