Merge pull request #95 from renderforest/contributing

src(CONTRIBUTING): add documentation for contributing to this project

Author: narekhovhannisyan

CONTRIBUTING.md

@@ -0,0 +1,99 @@
+# Contributing to renderforest-sdk-php
+
+## Code Contributions
+
+#### Step 1: Clone
+
+Clone the project on [GitHub](https://github.com/renderforest/renderforest-sdk-php.git)
+   
+   ``` bash
+   $ git clone https://github.com/renderforest/renderforest-sdk-php.git
+   $ cd renderforest-sdk-php
+   ```
+   
+For developing new features and bug fixes, the stage branch should be pulled and built upon.
+
+#### Step 2: Branch
+
+Create a new topic branch to contain your feature, change, or fix:
+
+   ``` bash
+   $ git checkout -b <topic-branch-name>
+   ```
+
+#### Step 3: Commit
+
+Make sure git knows your name and email address:
+
+   ``` bash
+   $ git config --global user.name "Example User"
+   $ git config --global user.email "[email protected]"
+   ```
+    
+Add and commit:
+
+   ``` bash
+   $ git add my/changed/files
+   $ git commit
+   ```
+    
+Commit your changes in logical chunks. Please adhere to these [Commit message guidelines](#commit-message-guidelines)
+   or your code is unlikely be merged into the main project.
+
+#### Step 4: Rebase
+
+Use git rebase to synchronize your work with the main repository.
+
+   ``` bash
+   $ git fetch upstream
+   $ git rebase upstream/master
+   ```
+   
+#### Step 5: Push
+
+Push your topic branch:
+
+   ``` bash
+   $ git push origin <topic-branch-name>
+   ```
+
+#### Step 6: Pull Request
+
+Open a Pull Request with a clear title and description.
+
+
+## Commit message guidelines
+
+
+The commit message should describe what changed and why.
+
+   1. The first line should:
+       * contain a short description of the change
+       * be 60 characters or less
+       * be prefixed with the name of the changed subsystem
+       * be entirely in lowercase with the exception of proper nouns, acronyms, and the words that refer to code,
+         like function/variable names
+        
+       Examples:
+       
+       ```
+        lib: add changeTitle method to Sites
+        deps: add mime package to dependencies
+        examples: fix typos in Aws_sdk.php
+        helpers: refactor base64_helper.php
+       ```
+   2. Keep the second line blank. 
+          
+   3. Wrap all other lines at 72 columns:
+      * describe each line in logical chunks
+      * start each line with: space hyphen space ( - ...)
+      * be entirely in lowercase with the exception of proper nouns, acronyms, and the words that refer to code,
+        like function/variable names
+      
+      Examples:
+      
+      ```    
+        - add private method _awsMimeType to Aws_sdk to check media type
+        - refactor private method from Auth class
+        - add PhpDoc on User class method
+      ```