Call bash explicitly

Author: liufengyun

.appveyor.yml

@@ -2,7 +2,7 @@ version: '{build}'
 os: Windows Server 2012
 install:
   - cmd: choco install sbt -ia "INSTALLDIR=""C:\sbt"""
-  - cmd: SET PATH=C:\sbt\bin;%JAVA_HOME%\bin;%PATH%
+  - cmd: SET PATH=C:\MinGW\msys\1.0\bin;C:\sbt\bin;%JAVA_HOME%\bin;%PATH%
   - cmd: SET SBT_OPTS=-XX:MaxPermSize=2g -Xmx4g
 clone_script:
   - pwd
@@ -12,16 +12,14 @@ clone_script:
   - git submodule update --init --recursive --depth 50 --jobs 3
 build_script:
   - pwd
-  - ls
-  - ./project/scripts/sbt compile
-  - ./project/scripts/sbt "dotty-bootstrapped/compile"
+  - bash project/scripts/sbt compile
+  - bash project/scripts/sbt "dotty-bootstrapped/compile"
 test_script:
   - pwd
-  - ls
-  - ./project/scripts/sbt test
-  - ./project/scripts/cmdTests
-  - ./project/scripts/sbt "dotty-bootstrapped/test"
-  - ./project/scripts/bootstrapCmdTests
+  - bash project/scripts/sbt test
+  - bash project/scripts/cmdTests
+  - bash project/scripts/sbt "dotty-bootstrapped/test"
+  - bash project/scripts/bootstrapCmdTests
 cache:
   - C:\sbt\
   - C:\Users\appveyor\.ivy2