Prune down docker image (#1286)

* Improve `Dockerfile` to run fewer commands and re-use the build cache

Co-authored-by: Joe Atzberger <atz@corelight.com>
Co-authored-by: Kevin Chung <kchung@nyu.edu>

.dockerignore

@@ -5,3 +5,10 @@ CTFd/*.db
 CTFd/uploads/**/*
 .ctfd_secret_key
 .data
+.git
+.codecov.yml
+.dockerignore
+.github
+.gitignore
+.prettierignore
+.travis.yml

Dockerfile

@@ -1,17 +1,24 @@
 FROM python:3.7-alpine
-RUN apk update && \
-    apk add python python-dev linux-headers libffi-dev gcc make musl-dev py-pip mysql-client git openssl-dev
-RUN adduser -D -u 1001 -s /bin/bash ctfd
-
 WORKDIR /opt/CTFd
 RUN mkdir -p /opt/CTFd /var/log/CTFd /var/uploads
 
-COPY requirements.txt .
-
-RUN pip install -r requirements.txt
+RUN apk update && \
+    apk add \
+        python \
+        python-dev \
+        linux-headers \
+        libffi-dev \
+        gcc \
+        make \
+        musl-dev \
+        py-pip \
+        mysql-client \
+        git \
+        openssl-dev
 
 COPY . /opt/CTFd
 
+RUN pip install -r requirements.txt
 RUN for d in CTFd/plugins/*; do \
         if [ -f "$d/requirements.txt" ]; then \
             pip install -r $d/requirements.txt; \
@@ -19,8 +26,8 @@ RUN for d in CTFd/plugins/*; do \
     done;
 
 RUN chmod +x /opt/CTFd/docker-entrypoint.sh
-RUN chown -R 1001:1001 /opt/CTFd
-RUN chown -R 1001:1001 /var/log/CTFd /var/uploads
+RUN adduser -D -u 1001 -s /bin/sh ctfd
+RUN chown -R 1001:1001 /opt/CTFd /var/log/CTFd /var/uploads
 
 USER 1001
 EXPOSE 8000