Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -40,4 +40,39 @@ Our process for accepting changes operates by [Pull Request (PR)](https://help.g
 
 1.  Once you have integrated comments, or waited for feedback, a Lieutenant should merge your changes in!
 
+### Building and BuildTypes
+
+The default build is debug, with this variant you can use a debugger while developing. To install the application click the run button in Android Studio with the `app` configuration selected while you have a device connected.
+All other build types but release can be ignored, the release build is what gets uploaded to the play store and can be built locally with the dummy credentials/keystore provided.
+
+Unit tests are located in app/src/test and to run them locally you can use the gradle command:
+
+        gradlew testKiwixDebugUnitTest
+        
+or the abbreviated:
+
+        gradlew tKDUT
+        
+Automated tests that require a connected device are located in app/src/androidTest & app/src/androidTestKiwix, to run them locally you can use the gradle command:
+
+        gradlew connectedKiwixDebugAndroidTest
+       
+or the abbreviated:
+
+        gradlew cKDAT
+        
+To generate coverage reports for your unit tests run:
+
+        gradlew jacocoTestKiwixDebugUnitTest    
+            
+To generate coverage reports for your automated tests run:
+
+        gradlew createKiwixDebugCoverageReport
+
+All local test results can be seen under app/build/reports/
+
+All PRs will have all these tests run and a combined coverage report will be attached, if coverage is to go down the PR will be marked failed.
+On Travis CI the automated tests are run on an emulator.
+To learn more about the commands run on the CI please refer to [.travis.yml](https://github.com/kiwix/kiwix-android/blob/master/.travis.yml)
+
 _These guidelines are based on [Tools for Government Data Archiving](https://github.com/edgi-govdata-archiving/overview/blob/master/CONTRIBUTING.md)'s._