fix(guide): restructure curriculum guide articles (#36501)

* fix: restructure certifications guide articles
* fix: added 3 dashes line before prob expl
* fix: added 3 dashes line before hints
* fix: added 3 dashes line before solutions

guide/english/certifications/apis-and-microservices/mongodb-and-mongoose/create-a-model/index.md

@@ -2,40 +2,47 @@
 title: Create a Model
 ---
 
+# Create a Model
+
+
+---
+## Solutions
+
+<details><summary>Solution 1 (Click to Show/Hide)</summary>
+
 There are 3 things to do in this challenge. You can click each item to see the code.
 
-<details>
-  <summary>Assign Mongoose Schema to a variable. This is not necessary but will make your code easier to read.</summary>
+**Assign Mongoose Schema to a variable**
+This is not necessary but will make your code easier to read.
 
 ```javascript
 const Schema = mongoose.Schema;
 ```
-</details>
 
 See the [Mongoose docs](https://mongoosejs.com/docs/guide.html) first where is a lot of useful stuff. 
 When you are building schema you can use either of three options for name validation
-```js
+```
+
 name: String
 name: {type: String}
 name: {type: String, required: true} //preferred
 ```
 
-<details>
-  <summary>Create Person schema.</summary>
+**Create Person schema.**
 
 ```javascript
 const personSchema = new Schema({
   name: { type: String, required: true },
   age: Number,
-  favoriteFoods:   [String]
+  favoriteFoods: [String]
 });
 ```
 **Note**: If you choose to skip the first step, you have to use `mongoose.Schema` instead of `Schema`.
-</details>
-<details>
-  <summary>Create Person model from the schema.</summary>
+
+**Create Person model from the schema.**
 
 ```javascript
-const Person = mongoose.model('Person', personSchema);
+const Person = mongoose.model("Person", personSchema);
 ```
 </details>
+