Change Django sample so that mysqlclient is not installed by default (GoogleCloudPlatform#2218)

Author: andrewsg

appengine/flexible/django_cloudsql/mysite/settings.py

@@ -78,19 +78,34 @@
 # https://docs.djangoproject.com/en/1.8/ref/settings/#databases
 
 # [START dbconfig]
+
+# The following DATABASES configuration is for PostgreSQL. If you are using
+# MySQL, use the commented-out block that follows this one instead. In this
+# case, please also follow the commented instructions in requirements.txt.
+
 DATABASES = {
     'default': {
-        # If you are using Cloud SQL for MySQL rather than PostgreSQL, set
-        # 'ENGINE': 'django.db.backends.mysql' instead of the following.
         'ENGINE': 'django.db.backends.postgresql',
         'NAME': 'polls',
         'USER': '<your-database-user>',
         'PASSWORD': '<your-database-password>',
-        # For MySQL, set 'PORT': '3306' instead of the following. Any Cloud
-        # SQL Proxy instances running locally must also be set to tcp:3306.
         'PORT': '5432',
     }
 }
+
+# Uncomment this DATABASES block and use it instead of the above if you are
+# using MySQL. Also follow the commented instructions in requirements.txt.
+
+# DATABASES = {
+#     'default': {
+#         'ENGINE': 'django.db.backends.mysql',
+#         'NAME': 'polls',
+#         'USER': '<your-database-user>',
+#         'PASSWORD': '<your-database-password>',
+#         'PORT': '3306',
+#     }
+# }
+
 # In the flexible environment, you connect to CloudSQL using a unix socket.
 # Locally, you can use the CloudSQL proxy to proxy a localhost connection
 # to the instance

appengine/flexible/django_cloudsql/requirements.txt

@@ -1,5 +1,5 @@
 Django==2.1.9
-mysqlclient==1.4.1
+# mysqlclient==1.4.1  # Uncomment this line if using MySQL
 wheel==0.32.3
 gunicorn==19.9.0
-psycopg2==2.7.7
+psycopg2==2.7.7  # Comment this line out if using MySQL