Updated codebase for 2019.

.gitignore

@@ -2,5 +2,4 @@
 *.pyo
 
 .idea
-.buildozer
 bin

diet.py

@@ -3,14 +3,13 @@ from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import sessionmaker, relationship
 
 
-Persisted = declarative_base()
+Persisted = declarative_base()  # pylint: disable=invalid-name
 
 
 class DietDatabase(object):
     @staticmethod
     def construct_mysql_url(authority, port, database, username, password):
-        return 'mysql+mysqlconnector://{username}:{password}@{authority}:{port}/{database}' \
-            .format(authority=authority, port=port, database=database, username=username, password=password)
+        return f'mysql+mysqlconnector://{username}:{password}@{authority}:{port}/{database}'
 
     @staticmethod
     def construct_in_memory_url():
@@ -18,7 +17,7 @@ class DietDatabase(object):
 
     def __init__(self, url):
         self.engine = create_engine(url)
-        self.Session = sessionmaker()
+        self.Session = sessionmaker()  # pylint: disable=invalid-name
         self.Session.configure(bind=self.engine)
 
     def ensure_tables_exist(self):

diet_installer.py

-# -*- coding: utf-8; -*-
-
 from sys import stderr
 
 from sqlalchemy.exc import SQLAlchemyError
@@ -10,7 +8,7 @@ from diet import DietDatabase
 
 
 def add_starter_data(session):
-    pass  # TODO: stub
+    pass
 
 
 def main():
@@ -25,7 +23,7 @@ def main():
         print('Records created.')
     except SQLAlchemyError as exception:
         print('Database setup failed!', file=stderr)
-        print('Cause: {exception}'.format(exception=exception), file=stderr)
+        print(f'Cause: {exception}', file=stderr)
         exit(1)