Update Contributing Guide (#876)

* added a common problems section in CONTRIBUTING.md

* added a common problems section in CONTRIBUTING.md and a new file listing common problems

* Update COMMON_ERRORS.md

COMMON_ERRORS.md

@@ -0,0 +1,13 @@
+# Common Problems with First Setup
+
+### SDK Location not found. Define location with an ANDROID_SDK_ROOT environment variable. (expo modules error)
+
+If you're on windows, you'll need to edit your system (system wide)/user (just you) environment variables. You'll want to add an environment variable named **ANDROID_SDK_ROOT** (legacy env variable name) and **ANDROID_HOME** that points to your android studio's sdk location. It'll most likely look something like this:
+
+C:\Users\\**Username**\AppData\Local\Android\Sdk (copy paste this into the box)
+
+Delete your node_modules folder, invalidate caches and restart in android studio and restart your machine. Follow the steps again in the [setup section](./CONTRIBUTING.md#setup).
+
+### '.' is not recognized as an internal or external command, operable program or batch file. (npm run buildRelease error)
+
+Run this line in the terminal instead: ```cd android ; ./gradlew clean ; ./gradlew assembleRelease```

CONTRIBUTING.md

@@ -26,6 +26,10 @@ npm install
 npm run buildRelease
 ```
 
+### Common Problems with First Setup
+
+Please refer to this [file](./COMMON_ERRORS.md)
+
 ### Developing on Android
 
 You will need an Android device or emulator connected to your computer as well as an IDE of your choice. (eg: vscode)
@@ -57,4 +61,4 @@ codebase, however you can always check to see if the source code is compliant by
 
 ```bash
 npm run lint
-```
+```