add oauth extension
remove oauth client registry.

it already embeded.
basic oauth implemention
move oauth to auth directory
add basic permission.
include flask login
add user model with salted hash password
add foreign key refs
add user table to sql.

1. rename from polaris.sql to postgres.sql, as multiple db backend may
be supported in the future.
2. add a 'pl_' prefix for all table.
add 'pl_' prefix to tables
init sign up page.
models lambda and table name bug fix
unique for user email
basic signup function
add user login
change owner to user_id for better foreign key ref
support oauth signup and login.

will create a new account with random generated password for oauth
signup.
better default route rule
use sha1 for random password generate.

inspired by wtform csrf token.
enable csrf token validate for ajax requests.