Cannot create database with SQLAlchemy

I am trying to run my create_db.py file to create the posts.db database, but it will not get created in my project directory. And when I run the main file for the blog and try to login in I get the error below.

I have looked up this error and seen that other people have gotten it as well and asked about it here on Stackoverflow, but none of them seems to help me. I have read that this could be because something in my blog.py file is running main before the database gets created. But, I am thinking that it has something to do with the configuration. Mainly the PATH of the database could be getting mixed up with the app.config['SQLAlCHEMY_DATABASE_URI'] = 'sqlite:///' line.

Any ideas?

Here is the error

sqlalchemy.exc.OperationalError

OperationalError: (OperationalError) no such table: posts u'SELECT posts.id AS posts_id, posts.title AS posts_title, posts.post AS posts_post \nFROM posts' ()

OperationalError: (OperationalError) no such table: posts u'SELECT posts.id AS posts_id, posts.title AS posts_title, posts.post AS posts_post \nFROM posts' ()

Here is my code. There are three files here: blog.py, models.py, create_db.py

blog.py # controller of blog app

from flask import Flask, render_template, request, session,\
    flash, redirect, url_for, g
from flask.ext.sqlalchemy import SQLAlchemy
import sqlite3
from functools import wraps


# create the application object
app = Flask(__name__)

# configuration
app.secret_key = 'x13xa8xf5}[xfexd4Zxb8+x07=7xc9xe1Bxcfxbdt.ox87oxc9'
app.config['SQLAlCHEMY_DATABASE_URI'] = 'sqlite:///'

# create sqlalchemy object

db = SQLAlchemy(app)

from models import *

# login required decorator
def login_required(test):
    @wraps(test)
    def wrap(*args, **kwargs):
        if 'logged_in' in session:
            return test(*args, **kwargs)
        else:
            flash('You need to login first.')
            return redirect(url_for('login'))
    return wrap

@app.route('/', methods = ['GET','POST'])
def login():
    error = None
    if request.method == 'POST':
        if request.form['username'] != 'admin' or request.form['password'] != 'admin':
            error = 'Invalid Credentils. Please try again.'
        else:
            session['logged_in'] = True
            return redirect(url_for('main'))
    return render_template('login.html', error=error)

@app.route('/main')
@login_required
def main():
    posts = db.session.query(BlogPost).all()
    return render_template('main.html', posts=posts)

@app.route('/add', methods=['POST'])
@login_required
def add():
    title = request.form['title']
    post = request.form['post']
    if not title or not post:
        flash("All fields are required. Please try again.")
        return redirect(url_for('main'))
    else:
        db.session.add(title)
        db.session.add(post)
        db.session.commit()
        db.session.close()
        flash('New entry was successfully posted!')
        return redirect(url_for('main'))


@app.route('/logout')
def logout():
    session.pop('logged_in', None)
    flash('You were logged out')
    return redirect(url_for('login'))

def connect_db():
    return sqlite.connect('posts.db')

if __name__ == '__main__':
    app.run(debug = True)

models.py:

from blog import db

class BlogPost(db.Model):

    __tablename__ = "posts"

    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String, nullable=False)
    post = db.Column(db.String, nullable=False)

    def __init__(self, title, post):
        self.title = title
        self.post = post

    def __repr__(self):
        return '<title {}'.format(self.title)

create_db.py

from blog import db
from models import BlogPost

# create the database and the db tables
db.create_all()

# insert
db.session.add(BlogPost("Good","I\'m good."))
db.session.add(BlogPost("Well","I\'m well."))
db.session.add(BlogPost("Post","I\'m a post."))

# commit the changes

db.session.commit()