Raspberrypi docker image error

[invictusro]

Hello guys so I do want to build a docker container. I do have a Raspberrypi with a flask app and I'm using multiple libraries.
Every library is installed succesfully until I hit this:

Running setup.py install for ssh2-python: started
Running setup.py install for ssh2-python: finished with status 'error'

This seems to be the cause of the error:

/bin/sh: 1: cmake: not found

I have tried to follow some questions from stack but none of them worked. Does any of you know what can be the cause ?
Here are the packages installed by me:

mysql-connector==2.2.9
Flask==1.0.2
getmac==0.8.2
ssh2-python==0.19.0

[aveach]

Install cmake in your docker image before attempting to install this package?

sudo apt-get install cmake