refactor to make way for dockerization

app/app.py

@@ -13,7 +13,7 @@ basedir = os.path.abspath(os.path.dirname(__file__))
 app = Flask(__name__)
 app.config['SECRET_KEY'] = 'HwG55rpe83jcaglifXm8NuF4WEeXyJV4'
 app.config['SQLALCHEMY_DATABASE_URI'] =\
-           'sqlite:///' + os.path.join(basedir, 'database.db')
+           'sqlite:///' + os.path.join(basedir, os.environ['SQLITE_DB'])
 app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
 db.init_app(app)