Update CONTRIBUTING - contribution guideline to branch off development

.github/PULL_REQUEST_TEMPLATE

@@ -12,7 +12,7 @@ Closes #2
 ### Checklist
 - [ ] I have made a material change to the repo (functionality, testing, spelling, grammar)
 - [ ] I have read the [Contribution Guide] and my PR follows them.
-- [ ] I updated my branch with the master branch.
+- [ ] I updated my branch with the development branch.
 - [ ] I have added tests that prove my fix is effective or that my feature works
 - [ ] I have added necessary documentation about the functionality in the appropriate .md file
 - [ ] I have added in line documentation to the code I modified

CONTRIBUTING.md

@@ -1,4 +1,4 @@
-Hello! Thank you for choosing to help contribute to one of the SendGrid open source libraries. There are many ways you can contribute and help is always welcome.  We simply ask that you follow the following contribution policies.
+Hello! Thank you for choosing to help contribute to one of the SendGrid open source libraries. There are many ways you can contribute and help is always welcome. We simply ask that you follow the following contribution policies.
 
 - [CLAs and CCLAs](#cla)
 - [Roadmap & Milestones](#roadmap)
@@ -59,6 +59,8 @@ In order to make the process easier, we've included a [sample bug report templat
 
 We welcome direct contributions to the sendgrid-php code base. Thank you!
 
+Please note that we utilize the [Gitflow Workflow](https://www.atlassian.com/git/tutorials/comparing-workflows/gitflow-workflow) for Git to help keep project development organized and consistent.
+
 ### Development Environment ###
 
 #### Install and Run Locally ####
@@ -161,10 +163,11 @@ Please run your code through:
    git pull upstream <dev-branch>
    ```
 
-3. Create a new topic branch (off the main project development branch) to
+3. Create a new topic branch off the `development` branch to
    contain your feature, change, or fix:
 
    ```bash
+   git checkout development
    git checkout -b <topic-branch-name>
    ```
 
@@ -178,10 +181,10 @@ Please run your code through:
 
 4b. Create or update the example code that demonstrates the functionality of this change to the code.
 
-5. Locally merge (or rebase) the upstream development branch into your topic branch:
+5. Locally merge (or rebase) the upstream `development` branch into your topic branch:
 
    ```bash
-   git pull [--rebase] upstream master
+   git pull [--rebase] upstream development
    ```
 
 6. Push your topic branch up to your fork:
@@ -191,7 +194,7 @@ Please run your code through:
    ```
 
 7. [Open a Pull Request](https://help.github.com/articles/using-pull-requests/)
-	with a clear title and description against the `master` branch. All tests must be passing before we will review the PR.
+	with a clear title and description against the `development` branch. All tests must be passing before we will review the PR.
 
 If you have any additional questions, please feel free to [email](mailto:[email protected]) us or create an issue in this repo.