Add solargraph usage docs

doc/development/contributing/style_guides.md

@@ -100,6 +100,8 @@ Our codebase style is defined and enforced by [RuboCop](https://github.com/ruboc
 You can check for any offenses locally with `bundle exec rubocop --parallel`.
 On the CI, this is automatically checked by the `static-analysis` jobs.
 
+Additionally it is possible to integrate RubCop with several IDEs. [solargraph doc](../developing_with_solargraph.md) page describes how to integrate RubCop in to supported IDEs using [solargraph](https://github.com/castwide/solargraph) gem.
+
 For RuboCop rules that we have not taken a decision on yet, we follow the
 [Ruby Style Guide](https://github.com/rubocop-hq/ruby-style-guide),
 [Rails Style Guide](https://github.com/rubocop-hq/rails-style-guide), and

doc/development/developing_with_solargraph.md

+# Using solargraph
+
+Gemfile packages [solargraph](https://github.com/castwide/solargraph) language server for additional intellisense and code formatting capabilities with editors that support it.
+
+Example configuration for solargraph can be found in [.solargraph.yml.example](/.solargraph.yml.example) file. Copy the contents of this file to `.solargraph.yml` file for language server to pick this configuration up. Since `.solargraph.yml` configuration file is ignored by Git, it's possible to adjust configuration according to your needs.
+
+Refer to particular IDE plugin documentation on how to integrate it with solargraph language server:
+
+- **Visual Studio Code**
+  - GitHub: [vscode-solargraph](https://github.com/castwide/vscode-solargraph)
+
+- **Atom**
+  - GitHub: [atom-solargraph](https://github.com/castwide/atom-solargraph)
+
+- **Vim**
+  - GitHub: [LanguageClient-neovim](https://github.com/autozimu/LanguageClient-neovim)
+
+- **Emacs**
+  - GitHub: [emacs-solargraph](https://github.com/guskovd/emacs-solargraph)
+
+- **Eclipse**
+  - GitHub: [eclipse-solargraph](https://github.com/PyvesB/eclipse-solargraph)