update gitlab ci to build and publish docs also to publish a release build

.gitlab-ci.yml

@@ -1,6 +1,21 @@
 image: rascul3/rust:latest
 
-build:
+release-build:
     stage: build
     script:
-  - cargo build
+        - cargo build --release
+        - mkdir public
+        - mv target/release/rewot public/rewot-bin
+    artifacts:
+        paths:
+            - public/
+
+doc:
+    stage: doc
+	script:
+	    - cargo doc
+	    - mkdir public
+	    - mv target/doc public/
+    artifacts:
+        paths:
+            - public/