added alpine-based docker build

.dockerignore

@@ -0,0 +1,3 @@
+*
+!/Makefile
+!/src/

Dockerfile

@@ -0,0 +1,18 @@
+FROM alpine:3.9 as build
+
+RUN apk add --no-cache \
+    fuse3-dev \
+    gcc \
+    gpgme-dev \
+    libc-dev \
+    make \
+    pkgconf
+
+RUN apk add --no-cache fuse `# convenient`
+
+RUN adduser -S build
+USER build
+
+COPY --chown=build:nogroup . /rgpgfs
+WORKDIR /rgpgfs
+RUN make

README.md

@@ -11,11 +11,23 @@ Run `make` after installing
 and
 [gpgme](https://www.gnupg.org/software/gpgme/index.html).
 
+### Debian / Ubuntu
+
 ```sh
 apt-get install libfuse3-dev libgpgme-dev
 make
 ```
 
+### Docker 🐳
+
+```sh
+docker build -t rgpgfs .
+docker run --rm -it --device /dev/fuse \
+    --cap-add SYS_ADMIN rgpgfs
+```
+
+You may need to add `--security-opt apparmor:unconfined`.
+
 ## Usage
 
 ```sh