docker: copy to avoid local host dependency

docker/Dockerfile

@@ -14,10 +14,16 @@ RUN curl https://download.imagemagick.org/ImageMagick/download/ImageMagick.tar.g
  && cd .. \
  && rm -r ImageMagick-${MAGICK_VERSION}*
 
+WORKDIR /magick
+COPY build.rs .
+COPY Cargo.toml .
+COPY src src
+COPY tests tests
+
 RUN adduser --disabled-password --gecos '' magick-rust
+RUN chown -R magick-rust .
 
 USER magick-rust
 
-ENV USER=magick-rust LD_LIBRARY_PATH=/usr/local/lib
-
-WORKDIR /src
+ENV USER=magick-rust
+ENV LD_LIBRARY_PATH=/usr/local/lib

docker/docker-compose.yml

@@ -3,9 +3,7 @@ version: '3'
 services:
   magick-rust:
     build:
-      context: .
-      dockerfile: Dockerfile
-    volumes:
-      - ..:/src
+      context: ..
+      dockerfile: docker/Dockerfile
     stdin_open: true
     tty: true