Upgrade to Django 2.1 (#710)

* Upgrade to Django 2.0

* more models

* i18n foo

* Update setup.py

* Fix Sentry exception PRETIXEU-JC

* Enforce slug uniqueness

* Import sorting

* Upgrade to Django 2.1

* Travis config

* Try to fix PostgreSQL failure

* Smaller test matrix

* staticfiles→static

* Include request in all authenticate() calls

src/setup.py

@@ -1,4 +1,5 @@
 import os
+import sys
 from codecs import open
 from distutils.command.build import build
 from os import path
@@ -7,6 +8,27 @@ from setuptools import find_packages, setup
 
 from pretix import __version__
 
+CURRENT_PYTHON = sys.version_info[:2]
+REQUIRED_PYTHON = (3, 5)
+if CURRENT_PYTHON < REQUIRED_PYTHON:
+    sys.stderr.write("""
+==========================
+Unsupported Python version
+==========================
+This version of pretix requires Python {}.{}, but you're trying to
+install it on Python {}.{}.
+This may be because you are using a version of pip that doesn't
+understand the python_requires classifier. Make sure you
+have pip >= 9.0 and setuptools >= 24.2, then try again:
+    $ python -m pip install --upgrade pip setuptools
+    $ python -m pip install pretix
+This will install the latest version of pretix which works on your
+version of Python. If you can't upgrade your pip (or Python), request
+an older version of pretix:
+    $ python -m pip install "pretix<2"
+""".format(*(REQUIRED_PYTHON + CURRENT_PYTHON)))
+    sys.exit(1)
+
 here = path.abspath(path.dirname(__file__))
 
 # Get the long description from the relevant file
@@ -43,6 +65,7 @@ cmdclass = {
 setup(
     name='pretix',
     version=__version__,
+    python_requires='>={}.{}'.format(*REQUIRED_PYTHON),
     description='Reinventing presales, one ticket at a time',
     long_description=long_description,
     url='https://pretix.eu',
@@ -56,39 +79,39 @@ setup(
         'Topic :: Internet :: WWW/HTTP :: Dynamic Content',
         'Environment :: Web Environment',
         'License :: OSI Approved :: Apache Software License',
-        'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
-        'Framework :: Django :: 1.11'
+        'Programming Language :: Python :: 3.7',
+        'Framework :: Django :: 2.1'
     ],
 
     keywords='tickets web shop ecommerce',
     install_requires=[
-        'Django==1.11.*',
-        'djangorestframework==3.6.*',
+        'Django>=2.1,<2.2',
+        'djangorestframework==3.8.*',
         'python-dateutil==2.4.*',
         'pytz',
-        'django-bootstrap3==8.2.*',
+        'django-bootstrap3==10.0.*',
         'django-formset-js-improved==0.5.0.2',
-        'django-compressor==2.1',
+        'django-compressor==2.2.*',
         'django-hierarkey==1.0.*,>=1.0.2',
-        'django-filter==1.0.*',
-        'reportlab==3.4.*',
+        'django-filter==2.0.*',
+        'reportlab==3.5.*',
         'Pillow',
         'PyPDF2==1.26.*',
         'django-libsass',
         'libsass',
-        'django-otp==0.3.*',
+        'django-otp==0.4.*',
         'python-u2flib-server==4.*',
-        'django-formtools==2.0',
+        'django-formtools==2.1',
         'celery>=4.1.1,<4.2.0',
         'kombu==4.2.*',
-        'django-statici18n==1.3.*',
+        'django-statici18n==1.8.*',
         'inlinestyler==0.2.*',
         'BeautifulSoup4',
         'slimit',
         'lxml',
-        'static3==0.6.1',
+        'static3==0.7.*',
         'dj-static',
         'csscompressor',
         'django-markup',
@@ -96,14 +119,14 @@ setup(
         'bleach==2.*',
         'raven',
         'babel',
-        'paypalrestsdk==1.12.*',
+        'paypalrestsdk==1.13.*',
         'pycparser==2.13',
         'django-redis==4.7.*',
         'redis==2.10.5',
         'stripe==2.0.*',
         'chardet<3.1.0,>=3.0.2',
-        'mt-940==4.7',
-        'django-i18nfield>=1.2.1',
+        'mt-940==3.2',
+        'django-i18nfield>=1.4.0',
         'vobject==0.9.*',
         'pycountry',
         'django-countries',
@@ -111,12 +134,12 @@ setup(
         'defusedcsv',
         'vat_moss==0.11.0',
         'django-hijack==2.1.*',
-        'django-oauth-toolkit==1.1.*',
+        'django-oauth-toolkit==1.2.*',
         'idna==2.6',  # required by current requests
     ],
     extras_require={
         'dev': [
-            'django-debug-toolbar==1.7',
+            'django-debug-toolbar==1.9.1',
             'sqlparse==0.2.1',
             'pep8==1.5.7',
             'pyflakes==1.1.0',
@@ -127,7 +150,7 @@ setup(
             'pytest==3.6.*',
             'pytest-django',
             'isort',
-            'pytest-mock',
+            'pytest-mock==1.6.*',
             'pytest-rerunfailures',
             'pytest-warnings',
             'responses'