add gitflow basic configuration

We need to add to the .git/config file the following:

```
[gitflow "branch"]
	master = master
	develop = develop
[gitflow "prefix"]
	feature = feature/
	release = release/
	hotfix = hotfix/
	support = support/
	versiontag = v
```

We also need to create a develop branch.

This will allow us to start with the gitflow setup by default.

Aha! Link: https://saasler.aha.io/features/GENAPP-11