Enhancement to the redisbloom

[bilalsp]

@gkorland
User should be able to create create the object once and configure the application later to support it using init_app() method like other libraries SQLAlchemy, Bcrypt etc.

from redisbloom.client import Client

rb = Client()

def create_app():
     app = Flask(__name__)
     rb.init_app(app)
     return app

redisbloom should support configuration of Client object using 'app' configuration.