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/basic-node-and-express/chain-middleware-to-create-a-time-server.english.md

@@ -52,7 +52,11 @@ 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/basic-node-and-express/get-data-from-post-requests.english.md

@@ -46,7 +46,11 @@ 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/basic-node-and-express/get-query-parameter-input-from-the-client.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/basic-node-and-express/get-route-parameter-input-from-the-client.english.md

@@ -39,7 +39,11 @@ 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/basic-node-and-express/implement-a-root-level-request-logger-middleware.english.md

@@ -48,7 +48,11 @@ 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/basic-node-and-express/meet-the-node-console.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/basic-node-and-express/serve-an-html-file.english.md

@@ -43,7 +43,11 @@ 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/basic-node-and-express/serve-json-on-a-specific-route.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/basic-node-and-express/serve-static-assets.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/basic-node-and-express/start-a-working-express-server.english.md

@@ -47,7 +47,11 @@ 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/basic-node-and-express/use-body-parser-to-parse-post-requests.english.md

@@ -50,7 +50,11 @@ 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/basic-node-and-express/use-the-.env-file.english.md

@@ -38,7 +38,11 @@ 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>