Generate database schema diagram image automatically.

README.md

@@ -123,10 +123,29 @@ Check GET /api/v1/me/ for frontend feature gating.
 
 ---
 
+🗺️ Database Schema Diagram
+
+Generate an ER diagram image automatically from Django models:
+
+```bash
+python manage.py generate_schema_diagram
+```
+
+This command writes the diagram to:
+
+- `docs/images/db_schema.png`
+
+Then the README can show it directly:
+
+![Database schema diagram](docs/images/db_schema.png)
+
+The diagram is generated directly from Django model metadata and saved as a PNG image.
+
+---
+
 ⚠️ Important notes
 
-· core/settings.py currently uses development defaults (DEBUG=True, hardcoded DB credentials).
-    Switch to environment variables before production!
+· Environment is loaded from `.env` (see `.env.sample`), including DB settings.
 · Channel layer is in‑memory. Use Redis for production.
 · Browsable API is enabled only when DEBUG=True.
 
@@ -143,4 +162,3 @@ Detailed contracts and checklists are in the docs/ folder:
 
 
 
-!

courses/management/commands/generate_schema_diagram.py

@@ -0,0 +1,102 @@
+from math import ceil
+from pathlib import Path
+
+from django.apps import apps
+from django.core.management import BaseCommand
+from PIL import Image, ImageDraw, ImageFont
+
+
+class Command(BaseCommand):
+    help = "Generate DB schema diagram image directly from Django models."
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "--output",
+            default="docs/images/db_schema.png",
+            help="Output image path (default: docs/images/db_schema.png)",
+        )
+
+    def handle(self, *args, **options):
+        output = Path(options["output"])
+        output.parent.mkdir(parents=True, exist_ok=True)
+
+        model_specs = []
+        for app_label in ("accounts", "courses"):
+            app_config = apps.get_app_config(app_label)
+            for model in app_config.get_models():
+                fields = []
+                relations = []
+                for field in model._meta.get_fields():
+                    if field.auto_created and not field.concrete:
+                        continue
+                    if field.is_relation:
+                        rel_model = getattr(field, "related_model", None)
+                        if rel_model is not None:
+                            relations.append((field.name, rel_model.__name__))
+                            if field.concrete:
+                                fields.append(f"{field.name}: {field.__class__.__name__}")
+                    elif field.concrete:
+                        fields.append(f"{field.name}: {field.get_internal_type()}")
+                model_specs.append(
+                    {
+                        "name": model.__name__,
+                        "app": app_label,
+                        "fields": fields,
+                        "relations": relations,
+                    }
+                )
+
+        if not model_specs:
+            self.stdout.write(self.style.WARNING("No models found."))
+            return
+
+        font = ImageFont.load_default()
+        title_h = 20
+        line_h = 14
+        box_w = 360
+        box_gap_x = 48
+        box_gap_y = 28
+        max_field_lines = max(max(len(m["fields"]), 1) for m in model_specs)
+        box_h = title_h + (max_field_lines + 2) * line_h
+        cols = 3
+        rows = ceil(len(model_specs) / cols)
+        width = 48 + cols * box_w + (cols - 1) * box_gap_x + 48
+        height = 48 + rows * box_h + (rows - 1) * box_gap_y + 48
+
+        image = Image.new("RGB", (width, height), (250, 252, 255))
+        draw = ImageDraw.Draw(image)
+
+        positions = {}
+        for idx, spec in enumerate(model_specs):
+            row, col = divmod(idx, cols)
+            x = 48 + col * (box_w + box_gap_x)
+            y = 48 + row * (box_h + box_gap_y)
+            x2 = x + box_w
+            y2 = y + box_h
+            positions[spec["name"]] = (x, y, x2, y2)
+
+            fill = (236, 244, 255) if spec["app"] == "courses" else (239, 255, 244)
+            draw.rounded_rectangle((x, y, x2, y2), radius=10, fill=fill, outline=(80, 98, 130), width=2)
+            draw.text((x + 10, y + 6), f"{spec['name']}  ({spec['app']})", font=font, fill=(25, 40, 60))
+            draw.line((x + 8, y + title_h, x2 - 8, y + title_h), fill=(130, 146, 170), width=1)
+
+            for i, field_line in enumerate(spec["fields"][: max_field_lines + 1]):
+                draw.text((x + 10, y + title_h + 6 + i * line_h), field_line, font=font, fill=(36, 50, 72))
+
+        for spec in model_specs:
+            sx1, sy1, sx2, sy2 = positions[spec["name"]]
+            start = (sx2, (sy1 + sy2) // 2)
+            for field_name, target_name in spec["relations"]:
+                target = positions.get(target_name)
+                if not target:
+                    continue
+                tx1, ty1, tx2, ty2 = target
+                end = (tx1, (ty1 + ty2) // 2)
+                color = (90, 95, 110)
+                draw.line((start[0], start[1], end[0], end[1]), fill=color, width=2)
+                mx = (start[0] + end[0]) // 2 + 2
+                my = (start[1] + end[1]) // 2 - 10
+                draw.text((mx, my), field_name, font=font, fill=(70, 70, 80))
+
+        image.save(output.as_posix(), format="PNG")
+        self.stdout.write(self.style.SUCCESS(f"Schema diagram generated: {output.as_posix()}"))

docs/images/.gitkeep

@@ -0,0 +1 @@
+