misc: remove sqlite support (#52912)

README

@@ -13,7 +13,7 @@ Dependencies can be installed with pip,
  $ pip install -r requirements.txt
 
 It's then required to get the database configured (./manage.py migrate); by
-default it will create a db.sqlite3 file.
+default it will create a postgresqsl DB.
 
 You can then run the Django test server for a quick try (you should refer to
 the Django documentation for production deployments).

combo/settings.py

@@ -135,8 +135,7 @@ WSGI_APPLICATION = 'combo.wsgi.application'
 
 DATABASES = {
     'default': {
-        'ENGINE': 'django.db.backends.sqlite3',
-        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
+        'ENGINE': 'django.db.backends.postgresql_psycopg2',
     }
 }
 

tests/settings.py

@@ -1,6 +1,6 @@
 DATABASES = {
     'default': {
-        'ENGINE': os.environ.get('DB_ENGINE', 'django.db.backends.sqlite3'),
+        'ENGINE': os.environ.get('DB_ENGINE', 'django.db.backends.postgresql_psycopg2'),
         'NAME': 'combo-test-%s' % os.environ.get("BRANCH_NAME", "").replace('/', '-')[:45],
     }
 }

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 toxworkdir = {env:TMPDIR:/tmp}/tox-{env:USER}/combo/{env:BRANCH_NAME:}
-envlist = coverage-py3-django111-codestyle-pylint-{sqlite,pg},py3-django22-pg
+envlist = coverage-py3-django111-codestyle-pylint,py3-django22
 
 [testenv]
 usedevelop = True
@@ -10,7 +10,7 @@ setenv =
   TOX_WORK_DIR={toxworkdir}
   SETUPTOOLS_USE_DISTUTILS=stdlib
   coverage: COVERAGE=--cov-report xml --cov-report html --cov=combo/
-  pg: DB_ENGINE=django.db.backends.postgresql_psycopg2
+  DB_ENGINE=django.db.backends.postgresql_psycopg2
 passenv =
   BRANCH_NAME
 deps =
@@ -27,7 +27,7 @@ deps =
   pylint
   pylint-django
   django-webtest<1.9.3
-  pg: psycopg2-binary
+  psycopg2-binary
   django-mellon>=1.13
   vobject
   django-ratelimit<3