refactor: project structure

this commit introduces following changes:
- new project structure
- new improved dockerfile using debian:buster-slim as base image
- remove rust dependency tools by default

Author: joseluisq

.drone.yml

@@ -1,24 +1,89 @@
-pipeline:
-    publish:
-        image: plugins/docker
-        group: production
-        repo: joseluisq/rust-linux-darwin-builder
-        dockerfile: ./docker/Dockerfile
-        username:
-            from_secret: dockerhub_username
-        password:
-            from_secret: dockerhub_password
-        auto_tag: true
-        build_args:
-            - DOCKER_IMAGE_VERSION=${DRONE_TAG}
-        when:
-            event: tag
-        branch: master
-
-    notification:
-        image: plugins/slack
-        webhook:
-            from_secret: slack_webhook
-        channel: ci-cd
-        when:
-            status: [success, failure]
+---
+kind: pipeline
+type: docker
+name: development
+
+platform:
+  os: linux
+  arch: amd64
+
+steps:
+- name: build
+  image: docker
+  volumes:
+  - name: dockersock
+    path: /var/run/docker.sock
+  commands:
+    - docker build -f ./docker/Dockerfile -t joseluisq/rust-linux-darwin-builder:latest .
+
+- name: test
+  image: joseluisq/rust-linux-darwin-builder:latest
+  pull: if-not-exists
+  commands:
+    - ./docker/image_test.sh
+
+trigger:
+  event:
+    - push
+    - pull_request
+    - tag
+
+volumes:
+  - name: dockersock
+    host:
+      path: /var/run/docker.sock
+
+
+---
+kind: pipeline
+type: docker
+name: production
+
+platform:
+  os: linux
+  arch: amd64
+
+steps:
+- name: publish
+  image: plugins/docker
+  settings:
+    repo: joseluisq/rust-linux-darwin-builder
+    dockerfile: ./docker/Dockerfile
+    username:
+      from_secret: dockerhub_username
+    password:
+      from_secret: dockerhub_password
+    auto_tag: true
+    build_args:
+      - DOCKER_IMAGE_VERSION=${DRONE_TAG}
+
+trigger:
+  target:
+  - production
+
+
+---
+kind: pipeline
+type: docker
+name: notification
+
+platform:
+  os: linux
+  arch: amd64
+
+steps:
+- name: notify
+  image: plugins/slack
+  settings:
+    webhook:
+      from_secret: slack_webhook
+    channel: ci-cd
+
+depends_on:
+- development
+- production
+
+trigger:
+  status:
+  - success
+  - failure

.travis.yml

@@ -7,7 +7,7 @@ os:
   - linux
 
 script:
-- bash ./test-image
+- bash ./image_test.sh
 
 notifications:
   email:

Makefile

@@ -1,7 +1,7 @@
 build:
 	docker build \
 		-t joseluisq/rust-linux-darwin-builder:1 \
-		-f Dockerfile .
+		-f docker/Dockerfile .
 .PHONY: build
 
 release: