use docker drone

.drone.yml

@@ -1,19 +1,32 @@
 ---
 kind: pipeline
-type: exec
-name: test elseware
-
-platform:
-    os: linux
-    arch: amd64
+type: docker
+name: test libpso
 
 steps:
-- name: get rust
-  commands:
-  - rustup default nightly
 - name: cargo build
+  image: rustlang/rust:nightly
+  volumes:
+  - name: cache
+    path: /usr/local/cargo
+  - name: target-cache
+    path: /drone/src/target
   commands:
   - cargo build
 - name: cargo test
+  image: rustlang/rust:nightly
+  volumes:
+  - name: cache
+    path: /usr/local/cargo
+  - name: target-cache
+    path: /drone/src/target
   commands:
   - cargo test
+
+volumes:
+- name: cache
+  host:
+    path: /home/drone/.cargo
+- name: target-cache
+  host:
+    path: /home/drone/cargo-cache