Added CONTRIBUTING guidelines (#36)

* Added CONTRIBUTING guidelines
* keep Project.xml code style

.gitignore

@@ -43,7 +43,6 @@ crashlytics-build.properties
 fabric.properties
 
 # Styles
-.idea/codeStyles/Project.xml
 workspace.xml
 
 # VS Code files

CONTRIBUTING.md

@@ -0,0 +1,35 @@
+# Contributing to MockingBird
+
+Careem welcomes contributions of all kinds and sizes. This includes everything from simple bug reports to large features.
+
+Workflow
+--------
+
+We love GitHub issues!
+
+For small feature requests, an issue first proposing it for discussion or demo implementation in a PR suffice.
+
+For big features, please open an issue so that we can agree on the direction, and hopefully avoid investing a lot of time on a feature that might need reworking.
+
+Small pull requests for things like typos, bug fixes, etc are always welcome.
+
+### Code style
+
+* Use 4 spaces to indent your code
+* Do not use star imports
+
+DOs and DON'Ts
+--------------
+
+* DO follow kotlin standard coding conventions [coding style](https://kotlinlang.org/docs/coding-conventions.html)
+* DO include tests when adding new features. When fixing bugs, start with adding a test that highlights how the current behavior is broken.
+* DO keep the discussions focused. When a new or related topic comes up it's often better to create new issue than to side track the discussion.
+
+* DON'T submit PRs that alter licensing related files or headers. If you believe there's a problem with them, file an issue and we'll be happy to discuss it.
+
+Guiding Principles
+------------------
+
+* We allow anyone to participate in our projects. Tasks can be carried out by anyone that demonstrates the capability to complete them
+* Always be respectful of one another. Assume the best in others and act with empathy at all times
+* Collaborate closely with individuals maintaining the project or experienced users. Getting ideas out in the open and seeing a proposal before it's a pull request helps reduce redundancy and ensures we're all connected to the decision making process