add comment explaining back-end challenges don't need a solution (#37111)

* add solution to a challenge

add solution to the challenge: add-a-description-to-your-package-json

* add comment to all backend challenges
The comment expllains that these challenges don't need a solution.

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/chain-search-query-helpers-to-narrow-search-results.english.md

@@ -36,7 +36,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/create-a-model.english.md

@@ -65,7 +65,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/create-and-save-a-record-of-a-model.english.md

@@ -45,7 +45,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/create-many-records-with-model.create.english.md

@@ -36,7 +36,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/delete-many-documents-with-model.remove.english.md

@@ -37,7 +37,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/delete-one-document-using-model.findbyidandremove.english.md

@@ -36,7 +36,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/install-and-set-up-mongoose.english.md

@@ -41,7 +41,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/perform-classic-updates-by-running-find-edit-then-save.english.md

@@ -40,7 +40,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/perform-new-updates-on-a-document-using-model.findoneandupdate.english.md

@@ -37,7 +37,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/use-model.find-to-search-your-database.english.md

@@ -37,7 +37,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/use-model.findbyid-to-search-your-database-by-id.english.md

@@ -35,7 +35,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>

curriculum/challenges/english/05-apis-and-microservices/mongodb-and-mongoose/use-model.findone-to-return-a-single-matching-document-from-your-database.english.md

@@ -36,7 +36,11 @@ tests:
 <section id='solution'>
 
 ```js
-// solution required
+/**
+  Backend challenges don't need solutions, 
+  because they would need to be tested against a full working project. 
+  Please check our contributing guidelines to learn more.
+*/
 ```
 
 </section>