Create README_en

README_en

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+# :world_map: Xmap (Map of spots)
+## :question: A little help for the developers
+### How to open swagger doc:
+http://localhost:8080/swagger-ui/index.html
+### How to get a collection for postman:
+download last veriosn from https://github.com/ShulV/Xmap/tree/main/postman and import into postman 
+### How to initialize the database (PostgreSQL):
+<ul>
+  <li>Create all tables, indexes, functions and etc, also insert main refrerences: https://github.com/ShulV/Xmap/blob/main/sql/generate_DB.sql</li>
+  <li>Insert Countries/Regions/Cities references: https://github.com/ShulV/Xmap/blob/main/sql/insert_cities_regions_countries.sql</li>
+  <li>Insert a user and some real spots: https://github.com/ShulV/Xmap/blob/main/sql/additional_insert_scripts.sql</li>
+</ul>
+
+### How to view the relational model of a database:
+download and open in special UML-tools: https://github.com/ShulV/Xmap/blob/main/uml/relation_model.csv
+
+### How to write logs:
+<ul>
+  <li>Use snake_case for variables</li>
+  <li>Write variables in square brackets ('[', ']')</li>
+  <li>Write a colon (':') before variables block</li>
+  <li>.atInfo() - informing, .atWarn() - warnings, .atError - critical errors</li>
+</ul>
+
+```java
+logger.atInfo().log("Image info created: [image_info_id = '{}']", imageInfo.getId());
+```
+
+### How to name JSON keys: 
+(snake_case)
+```javascript
+"some_key_name" : "value" 
+```
+P.S. many JSON libraries (in Spring Framework), such as Jackson, support camelCase format out of the box.
+
+But snake_case is more convenient to read now.
+
+### Size of methods and classes:
+The maximum length of methods is 100 lines. The maximum class length is 1000 lines.
+
+If the size of a method or class exceeds these values, then new business logic can only be added in the form of calling methods of other functions. 
+
+But it is better to carefully refactor it!
+
+### Package structure:
+When more than one controller, service, repository, model, dto and etc. appears, we put them together in a package.
+
+### Dependency injection via lombok:
+Use @RequiredArgsConstructor and only it. 1 constructor for autowiring (without @Autowired annotation).
+Lombok will generate a constructor that accepts all required dependencies, marked as final or @NonNull.
+
+## :question: Unresolved app problems:
+<ul>
+  <li>Hibernate N+1 problem</li>
+  <li></li>
+  <li></li>
+  <li></li>
+  <li></li>
+</ul>