Initial commit. Basic models mostly done.

venv/lib/python3.8/site-packages/django/db/backends/base/client.py

@@ -0,0 +1,12 @@
+class BaseDatabaseClient:
+    """Encapsulate backend-specific methods for opening a client shell."""
+    # This should be a string representing the name of the executable
+    # (e.g., "psql"). Subclasses must override this.
+    executable_name = None
+
+    def __init__(self, connection):
+        # connection is an instance of BaseDatabaseWrapper.
+        self.connection = connection
+
+    def runshell(self):
+        raise NotImplementedError('subclasses of BaseDatabaseClient must provide a runshell() method')