Add docker-compose and entrypoint

src/app/docker_entrypoint.py

@@ -0,0 +1,56 @@
+#! /usr/bin/env python
+
+"""
+This is a Docker entrypoint that configures the container to run
+as the same uid of the user on the host container, rather than
+the Docker default of root. Aside from following security best
+practices, this makes it so that any files created by the Docker
+container are also owned by the same user on the host system.
+"""
+
+import sys
+import os
+import pwd
+import subprocess  # nosec
+
+HOST_UID = os.stat("/app").st_uid
+HOST_USER = "james"
+
+
+def does_username_exist(username):
+    try:
+        pwd.getpwnam(username)
+        return True
+    except KeyError:
+        return False
+
+
+def does_uid_exist(uid):
+    try:
+        pwd.getpwuid(uid)
+        return True
+    except KeyError:
+        return False
+
+
+if __name__ == "__main__":
+    if HOST_UID != os.geteuid():
+        if not does_uid_exist(HOST_UID):
+            username = HOST_USER
+            while does_username_exist(username):
+                username += "0"
+            home_dir = "/home/%s" % username
+            subprocess.check_call(
+                [  # nosec
+                    "useradd",
+                    "-d",
+                    home_dir,
+                    "-m",
+                    username,
+                    "-u",
+                    str(HOST_UID),
+                ]
+            )
+        os.environ["HOME"] = "/home/%s" % pwd.getpwuid(HOST_UID).pw_name
+        os.setuid(HOST_UID)
+    os.execvp(sys.argv[1], sys.argv[1:])  # nosec