add gitlab-ci.yml

.gitlab-ci.yml

+before_script:
+  - env
+
+image: $SERVER_LITE_DOCKER_IMAGE
+
+stages:
+  - ci
+  - build
+
+check:prebuilt:
+  stage: ci
+  script:
+    - cd $CI_PROJECT_DIR/Paddle
+    - ./paddle/scripts/paddle_build.sh check_style
+
+build:server:
+  image: $SERVER_LITE_DOCKER_IMAGE
+  stage: build
+  script:
+    - cd $CI_PROJECT_DIR/Paddle
+    - ./paddle/fluid/lite/tools/build.sh build_test_server
+
+build:mobile:
+    stage: build
+    image: $MOBILE_LITE_DOCKER_IMAGE
+    script:
+        - cd $CI_PROJECT_DIR/Paddle
+        - ./paddle/fluid/lite/tools/build.sh build_test_arm