I am getting the error using pip in my docker image.

```
FROM ubuntu:18.04

RUN apt-get update && apt-get install -y \
    software-properties-common
RUN add-apt-repository universe
RUN apt-get install -y \
    python3.6 \
    python3-pip

ENV PYTHONUNBUFFERED 1
RUN mkdir /api
WORKDIR /api

COPY . /api/
RUN pip install pipenv
RUN ls
RUN pipenv sync

```

I installed python 3.6 and pip3 but getting 

```
Step 9/11 : RUN pip install pipenv
 ---> Running in b184de4eb28e
/bin/sh: 1: pip: not found

```