add mongo init script

docker-compose.yml

@@ -10,4 +10,6 @@ services:
     environment:
       MONGO_INITDB_ROOT_USERNAME: root
       MONGO_INITDB_ROOT_PASSWORD: pass
-      MONGO_INITDB_DATABASE: test
+      MONGO_INITDB_DATABASE: test
+    volumes:
+      - ./docker-entrypoint-initdb.d/mongo-init.js:/docker-entrypoint-initdb.d/mongo-init.js:ro

docker-entrypoint-initdb.d/mongo-init.js

@@ -0,0 +1,54 @@
+db = db.getSiblingDB('test');
+
+db.createCollection('posts');
+db.createCollection('comments');
+
+db.posts.insertMany([
+    {
+        "author": {
+            "id": 1,
+            "name": "Dostoyevski"
+        },
+        "likes": 12,
+        "title": "Crime and Punishment"
+    },
+    {
+        "author": {
+            "id": 1,
+            "name": "Dostoyevski"
+        },
+        "likes": 100,
+        "title": "Notes From The Underground"
+    },
+    {
+        "author": {
+            "id": 2,
+            "name": "Marcus Aurelius"
+        },
+        "likes": 200,
+        "title": "Meditations"
+    }
+]);
+
+db.comments.insertMany([
+    {
+        "comment": "great read",
+        "likes": 3,
+        "postTitle": "Crime and Punishment"
+    },
+    {
+        "comment": "good info",
+        "likes": 0,
+        "postTitle": "Notes From The Underground"
+    },
+    {
+        "comment": "I liked this post",
+        "likes": 12,
+        "postTitle": "Notes From The Underground"
+    },
+    {
+        "comment": "very nice book",
+        "likes": 8,
+        "postTitle": "Meditations"
+    }
+])

readme.md

@@ -44,6 +44,8 @@ first create the mongo database.
 docker-compose up -d mongo
 ```
 
+It will generate a new MongoDB container and populate the collections with some data.
+
 then run
 
 ```bash