Implement simple CRUD operations

.env

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+PORT=3000

.gitignore

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+node_modules
+.idea
+dist

README.md

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-# CRUD-API-nodejs
+# CRUD-API-nodejs
+
+## Installation Guide
+
+1. Install dependencies:
+    ```
+    npm i 
+    ```
+2. Run start:dev script for running application in development mode
+    ```
+    npm run start:dev
+    ```
+    Or run start:prod script for running application in production mode
+
+    ```
+    npm run start:dev
+    ```
+
+3. Then use postman to test app.
+
+### Implemented endpoint api/users:
+
+- **GET** `api/users` is used to get all persons
+  - Server should answer with `status code` **200** and all users records
+    - **GET** `api/users/{userId}`
+        - Server should answer with `status code` **200** and record with `id === userId` if it exists
+        - Server should answer with `status code` **400** and corresponding message if `userId` is invalid (not `uuid`)
+        - Server should answer with `status code` **404** and corresponding message if record with `id === userId` doesn't exist
+    - **POST** `api/users` is used to create record about new user and store it in database
+        - Server should answer with `status code` **201** and newly created record
+        - Server should answer with `status code` **400** and corresponding message if request `body` does not contain **required** fields
+    - **PUT** `api/users/{userId}` is used to update existing user
+        - Server should answer with` status code` **200** and updated record
+        - Server should answer with` status code` **400** and corresponding message if `userId` is invalid (not `uuid`)
+        - Server should answer with` status code` **404** and corresponding message if record with `id === userId` doesn't exist
+    - **DELETE** `api/users/{userId}` is used to delete existing user from database
+        - Server should answer with `status code` **204** if the record is found and deleted
+        - Server should answer with `status code` **400** and corresponding message if `userId` is invalid (not `uuid`)
+        - Server should answer with `status code` **404** and corresponding message if record with `id === userId` doesn't exist
+
+### There is one predefined User in database for better testing
+```JSON
+{
+  "id": "876c2611-aa48-4ab4-9199-e8fc83e492b8",
+  "username": "Artur",
+  "age": 23,
+  "hobbies": [
+    "footbal"
+  ]
+}
+```