Use the MySQL connector that is recommended by Django

deployment/docker/standalone/Dockerfile

@@ -3,7 +3,7 @@ FROM debian:jessie
 RUN apt-get update && apt-get install -y supervisor python3 git python3-pip \
 	libxml2-dev libxslt1-dev python-dev python-virtualenv locales libffi-dev \
 	build-essential python3-dev zlib1g-dev libssl-dev npm gettext git \
-	libpq-dev \ 
+	libpq-dev libmysqlclient-dev \ 
 	--no-install-recommends
 
 WORKDIR /

src/pretix/settings.py

@@ -25,12 +25,9 @@ else:
 
 DEBUG = TEMPLATE_DEBUG = config.getboolean('django', 'debug', fallback=False)
 
-dbengine = 'django.db.backends.' + config.get('database', 'backend', fallback='sqlite3')
-if dbengine == 'django.db.backends.mysql':
-    dbengine = 'mysql.connector.django'
 DATABASES = {
     'default': {
-        'ENGINE': dbengine,
+        'ENGINE': 'django.db.backends.' + config.get('database', 'backend', fallback='sqlite3'),
         'NAME': config.get('database', 'name', fallback=os.path.join(BASE_DIR, 'db.sqlite3')),
         'USER': config.get('database', 'user', fallback=''),
         'PASSWORD': config.get('database', 'user', fallback=''),

src/requirements/mysql.txt

@@ -1,2 +1,2 @@
---allow-external mysql-connector-python 
-mysql-connector-python
+mysqlclient
+