[Feat] add contributing and more build instructions

Also tune up build.gradle for handling non existing key.properties file:
Simplify local dev with no signing keys.

BUILD.md

@@ -1,7 +1,35 @@
 # Builiding Instructions
 
-* You will need Flutter + Android Studio to be installed
 * It's best to just work on this on Android - the ios setup is far more complicated and I haven't managed to automate it.
 
-- Clone this repo
-- flutter build apk --flavor dev --debug
+## Enviroment setup
+
+1. Install [Flutter](https://flutter.dev/docs/get-started/install) through official guidilines
+2. As a part of flutter installation, you will need to install [Android Studio](https://developer.android.com/studio)
+3. Use [AVD manager](https://developer.android.com/studio/run/managing-avds) from Android Studio, to create device for local development.
+4. Project contains `:git_binding` dependency, so it needs Android NDK. You need to install through [SDK Manager](https://developer.android.com/studio/projects/install-ndk).
+5. Run command `flutter run --flavor dev --debug`: it will connect to availible device and run program.
+
+   1. Or you can run `flutter build apk --flavor dev --debug` and see apk under `build/app/outputs/apk/` folder
+
+6. You will see application on emulator, you are all setup. You can start with [app.dart](lib/app.dart) file to exploring code.
+
+## IDE Setup
+
+VS Code has great plugin for flutter, but you need to add args to launch.json.
+Example launch.json:
+
+``` json
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Flutter",
+            "request": "launch",
+            "type": "dart",
+            "args": ["--flavor", "dev"]
+        }
+    ]
+}
+```
+

CONTRIBUTING.md

@@ -0,0 +1,68 @@
+# Contributing
+
+Contributions are welcome, and they are greatly appreciated\! Every
+little bit helps, and credit will always be given.
+
+You can contribute in many ways:
+
+## Types of Contributions
+
+### Report Bugs
+
+Report bugs at <https://github.com/GitJournal/GitJournal/issues>.
+
+If you are reporting a bug, please include:
+
+  - Your operating system name and version.
+  - Any details about your local setup that might be helpful in
+    troubleshooting.
+  - Detailed steps to reproduce the bug.
+
+### Fix Bugs
+
+Look through the GitHub issues for bugs. Anything tagged with "bug" is
+open to whoever wants to implement it.
+
+### Implement Features
+
+Look through the GitHub issues for features. Anything tagged with
+"feature" is open to whoever wants to implement it.
+
+### Submit Feedback
+
+The best way to send feedback is to file an issue at
+<https://github.com/GitJournal/GitJournal/issues>.
+
+If you are proposing a feature:
+
+  - Explain in detail how it would work.
+  - Keep the scope as narrow as possible, to make it easier to
+    implement.
+  - Remember that this is a volunteer-driven project, and that
+    contributions are welcome :)
+
+## Get Started!
+
+Ready to contribute? Here's how to set up GitJournal for local development.
+
+1.  Fork the GitJournal repo on GitHub.
+
+2.  Clone your fork locally:
+    
+        $ git clone git@github.com:your_name_here/GitJournal.git
+
+3.  Refer to [build instructions](BUILD.md) for local development.
+
+4.  Create a branch for local development:
+    
+        $ git checkout -b name-of-your-bugfix-or-feature
+    
+    Now you can make your changes locally.
+
+5.  Commit your changes and push your branch to GitHub:
+    
+        $ git add .
+        $ git commit -m "Your detailed description of your changes."
+        $ git push origin name-of-your-bugfix-or-feature
+
+6.  Submit a pull request through the GitHub website.

android/app/build.gradle

@@ -28,6 +28,12 @@ def keystoreProperties = new Properties()
 def keystorePropertiesFile = rootProject.file('key.properties')
 if (keystorePropertiesFile.exists()) {
     keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
+} else {
+    // to simplify local development
+    keystoreProperties['keyAlias'] = 'local'
+    keystoreProperties['keyPassword'] = 'local'
+    keystoreProperties['storeFile'] = 'local'
+    keystoreProperties['storePassword'] = 'local'
 }
 
 android {