added comments, docstring, introduced functions

libraries/database/database.py

-from sqlalchemy.ext.declarative import declarative_base
-from modules.base.config import ConfigReader
+"""
+Database conn
+"""
 
+from sqlalchemy.ext.declarative import declarative_base
 from flask_sqlalchemy import SQLAlchemy
-from flask_babel import Babel
+# from flask_babel import Babel
 from flask import Flask
 
-Base = declarative_base()
+from modules.base.config import ConfigReader # pylint: disable=import-error
+
+def create_app(install_dir, uri):
+    """
+    creates flask app context
+    :param install_dir: Installdir of Aura
+    :param uri: Database connection uri
+    :return: Flask object
+    """
+    app = Flask(__name__, template_folder=install_dir + '/modules/web/templates')
+    app.config["SQLALCHEMY_DATABASE_URI"] = uri
+    app.config['BABEL_DEFAULT_LOCALE'] = 'de'
+    app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
+
+    return app
+
+
+def create_database():
+    """
+    creates sqlalchemy database connection
+    :return: SQLAlchemy object
+    """
+    #### load config ####
+    config = ConfigReader()
+    config.load_config()
 
-#### load config ####
-config = ConfigReader()
-config.load_config()
-
-#### read config ####
-install_dir = config.get(str("install_dir"))
-db_name = config.get(str("db_name"))
-db_user = config.get(str("db_user"))
-db_pass = config.get(str("db_pass"))
-db_host = config.get(str("db_host"))
-
-#### create database conn ####
-app = Flask(__name__, template_folder=install_dir+'/modules/web/templates')
-app.config["SQLALCHEMY_DATABASE_URI"] = "mysql://"+db_user+":"+db_pass+"@"+db_host+"/"+db_name+"?charset=utf8"
-app.config['BABEL_DEFAULT_LOCALE'] = 'de'
-app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
-
-db = SQLAlchemy(app)
-babel = Babel(app)
+    #### read config ####
+    install_dir = config.get(str("install_dir"))
+    db_name = config.get(str("db_name"))
+    db_user = config.get(str("db_user"))
+    db_pass = config.get(str("db_pass"))
+    db_host = config.get(str("db_host"))
+
+    #### create database conn ####
+    uri = "mysql://"+db_user+":"+db_pass+"@"+db_host+"/"+db_name+"?charset=utf8"
+
+    app = create_app(install_dir, uri)
+
+    database = SQLAlchemy(app)
+#    babel = Babel(app)
+
+    return app, database
+
+
+Base = declarative_base()
+APP, DB = create_database()