Update contributing guidelines (#731)

* Update CONTRIBUTING.md guidelines

* More edits

CONTRIBUTING.md

@@ -1,16 +1,44 @@
 # Contributing
 
 When contributing to this repository, please first discuss the change you wish to make via issue,
-email, or any other method with the owners of this repository before making a change. 
+email, or any other method with the maintainers of the repository before making a change. 
 
-Please note we have a code of conduct, please follow it in all your interactions with the project.
+Please note we have a code of conduct (`CODE-OF-CONDUCT.md`), please follow it in all your interactions with the project.
 
 ## Pull Request Process
 
-1. Ensure any install or build dependencies are removed before the end of the layer when doing a 
+### General rules
+
+1. Ensure any install or build dependencies have been removed before the end of the layer when composing a 
    build.
-2. Update the README.md with details of changes to the interface, this includes new environment 
+2. Update the `README.md` with details of changes to the interface, this includes new environment 
    variables, exposed ports, useful file locations and container parameters.
-3. Start Pull Request name with issue number (ex. #123)   
-4. You may merge the Pull Request in once you have the sign-off of two other developers, or if you 
-   do not have permission to do that, you may request the second reviewer to merge it for you.
+3. Start a pull request name with issue number (ex. #123).
+4. You may merge the pull request once you have the approval of two other developers. In case you 
+   don't have permissions to do that, you may request the second reviewer to merge it for you.
+
+### Branch naming
+
+In order to keep branch names understandable and similar please use the corresponding branch naming conventions.
+
+Generally speaking, it's a good idea to add a group/type prefix for a branch, e.g., 
+if you're working on a specific branch you could name your branch `issues/xxx`. 
+
+Here's a list of good examples:<br/>
+`issues/123`<br/>
+`feature/feature_name`<br/>
+`bugfix/fix_thing`<br/>
+
+### Code style
+
+There's a file called `checkstyle.xml` in project root under `etc` directory.<br/>
+You can import it into IntelliJ IDEA via checkstyle plugin. 
+
+### Naming conventions
+
+REST paths should be **lowercase** and consist of just **plural** nouns.<br/>
+Also, multiple words in a single path segment should be divided by a hyphen symbol (`-`).<br/>
+
+Query variable names should be formatted in `camelCase`.
+
+Model names should consist of just **plural** nouns and should be formatted in `camelCase` as well.