point out "good first issue" label

CONTRIBUTING.md

@@ -2,50 +2,52 @@
 
 ## Contribute to freqtrade
 
-Feel like our bot is missing a feature? We welcome your pull requests! Few pointers for contributions:
+Feel like our bot is missing a feature? We welcome your pull requests! 
+
+Issues labeled [good first issue](https://github.com/freqtrade/freqtrade/labels/good%20first%20issue) can be good first contributions, and will help get you familiar with the codebase.
+
+Few pointers for contributions:
 
 - Create your PR against the `develop` branch, not `master`.
-- New features need to contain unit tests and must be PEP8 
-
-conformant (max-line-length = 100).
+- New features need to contain unit tests and must be PEP8 conformant (max-line-length = 100).
 
 If you are unsure, discuss the feature on our [Slack](https://join.slack.com/t/highfrequencybot/shared_invite/enQtMjQ5NTM0OTYzMzY3LWMxYzE3M2MxNDdjMGM3ZTYwNzFjMGIwZGRjNTc3ZGU3MGE3NzdmZGMwNmU3NDM5ZTNmM2Y3NjRiNzk4NmM4OGE)
 or in a [issue](https://github.com/freqtrade/freqtrade/issues) before a PR.
 
-**Before sending the PR:**
+## Before sending the PR:
 
-## 1. Run unit tests
+### 1. Run unit tests
 
 All unit tests must pass. If a unit test is broken, change your code to 
 make it pass. It means you have introduced a regression.
 
-### Test the whole project
+#### Test the whole project
 
 ```bash
 pytest freqtrade
 ```
 
-### Test only one file
+#### Test only one file
 
 ```bash
 pytest freqtrade/tests/test_<file_name>.py
 ```
 
-### Test only one method from one file
+#### Test only one method from one file
 
 ```bash
 pytest freqtrade/tests/test_<file_name>.py::test_<method_name>
 ```
 
-## 2. Test if your code is PEP8 compliant
+### 2. Test if your code is PEP8 compliant
 
-### Install packages
+#### Install packages
 
 ```bash
 pip3.6 install flake8 coveralls
 ```
 
-### Run Flake8
+#### Run Flake8
 
 ```bash
 flake8 freqtrade
@@ -56,15 +58,15 @@ To help with that, we encourage you to install the git pre-commit
 hook that will warn you when you try to commit code that fails these checks. 
 Guide for installing them is [here](http://flake8.pycqa.org/en/latest/user/using-hooks.html).
 
-## 3. Test if all type-hints are correct
+### 3. Test if all type-hints are correct
 
-### Install packages 
+#### Install packages 
 
 ``` bash
 pip3.6 install mypy
 ```
 
-### Run mypy
+#### Run mypy
 
 ``` bash
 mypy freqtrade