add gunicorn for running it "properly"

README.md

@@ -1,3 +1,15 @@
+## Installation
+
+We are using [Pipenv](https://docs.pipenv.org) to make our lives easier:
+
+```sh
+git clone https://gitea.faelix.net/FAELIX/incident_handler.git
+cd incident_handler
+pipenv install --three
+```
+
+## Configuration
+
 Example `settings.cfg` file:
 
 ```python
@@ -22,3 +34,12 @@ PUBLIC_INCIDENT_PREFIX = "FI#"
 STATUS_PAGE_URL = "https://status.faelix.net/"
 INCIDENT_URL_SCHEME = STATUS_PAGE_URL + "event/%s/"
 ```
+
+## Running
+
+```sh
+export FIH_SETTINGS=~/incident_handler/settings.cfg
+export FLASK_APP=fih.py
+cd ~/incident_handler
+flask run -p 3333
+```