add ci

.gitlab-ci.yml

+image: "rust:latest"
+
+stages:
+  - test
+  - build
+
+before_script:
+  - apt-get update -q && apt-get install mingw-w64 -yqq
+  - rustup component add rustfmt
+  - rustup component add clippy
+  - rustup target add x86_64-pc-windows-gnu
+
+test:
+  script:
+    - cargo fmt -- --check
+    - cargo clippy --all-targets --all-features -- -D warnings
+    - cargo test
+build:
+  stage: build
+  script:
+    - cargo build --release
+    - cargo build --release --target x86_64-pc-windows-gnu
+  artifacts:
+    paths:
+      - target/release/minitransfer
+      - target/x86_64-pc-windows-gnu/release/minitransfer