docs: contribution guide (#78)

* feat: contribution guide

* chore: contribution update

* chore: lang fix

* chore: info about testing

* docs: style guides

* docs: add link to contribution to readme

CODE_OF_CONDUCT.md

@@ -0,0 +1,13 @@
+# Contributor Code of Conduct
+
+As contributors and maintainers of this project, we pledge to respect all people who contribute through reporting issues, posting feature requests, updating documentation, submitting pull requests or patches, and other activities.
+
+We are committed to making participation in this project a harassment-free experience for everyone, regardless of level of experience, gender, gender identity and expression, sexual orientation, disability, personal appearance, body size, race, ethnicity, age, or religion.
+
+Examples of unacceptable behavior by participants include the use of sexual language or imagery, derogatory comments or personal attacks, trolling, public or private harassment, insults, or other unprofessional conduct.
+
+Project maintainers have the right and responsibility to remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct. Project maintainers who do not follow the Code of Conduct may be removed from the project team.
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by opening an issue or contacting one or more of the project maintainers.
+
+This Code of Conduct is adapted from the [Contributor Covenant](http:contributor-covenant.org), version 1.0.0, available at https://www.contributor-covenant.org/version/1/0/0/code-of-conduct.html

CONTRIBUTING.md

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+# Contribution
+
+We welcome contributions to [Sourcerer App](https://github.com/sourcerer-io/sourcerer-app) by the community.
+
+See [README](https://github.com/sourcerer-io/sourcerer-app) for more information about prerequirements and building project.
+
+## How to report a problem
+
+Please search before creating a new issue. Feel free to add issues related to the app or [sourcerer](https://sourcerer.io) site.
+
+## Submitting сhanges
+
+* Open a new issue in the [issue tracker](https://github.com/sourcerer-io/sourcerer-app/issues).
+* Fork and clone the repo with `git clone https://github.com/your-username/sourcerer-app.git`.
+* Create a new branch based off the `develop` branch.
+* Make changes.
+* Make sure all tests pass.
+* Submit a pull request, referencing any issues it addresses.
+
+We will review your Pull Request as soon as possible. Thank you for contributing!
+
+## Integration testing
+
+We will work on a special environment for contributors in the nearest future. For now one should use his personal or additional account on site.
+
+## Style guides
+### Commit messages
+
+Format:
+```type(component): message (jira issue tag, github issue number with #)```
+
+Message types:
+* **feat** is used when new feature is provided;
+* **wip** is used when making regular commit and changes don't match any other types;
+* **fix** is used when you fix a bug;
+* **chore** is used when changes are about organization, not about logic;
+* **docs** is used when you add/change documentation.
+Component is a decomposition unit your commit affected. Write message in present simple.
+
+Examples:
+feat(logger): add rotating
+chore: remove redundant commas, add copyright
+wip: pass models to routers
+fix: program exit is prevented when button is pressed (COMP-1, #123)
+
+### Kotlin style guide
+* Code has a column limit of 80 characters.
+* Inline comments should be indented with 2 spaces from code.
+
+We are using [Kotlin Coding Conventions](https://kotlinlang.org/docs/reference/coding-conventions.html).
+
+## Code of conduct
+We value input from each member of the community, however we urge you to abide by [code of conduct](https://github.com/sourcerer-io/sourcerer-app/blob/master/CODE_OF_CONDUCT.md).

README.md

@@ -53,3 +53,8 @@ $ gradle build
 # Run the app
 $ java -jar build/libs/sourcerer-app.jar
 ```
+
+Contribution
+============
+
+We welcome contributions to Sourcerer App by the community. Check the [Contribution guide](https://github.com/sourcerer-io/sourcerer-app/blob/master/CONTRIBUTING.md)) for more information.