Add a Gitpod descriptor

.gitpod.yml

@@ -0,0 +1,53 @@
+# List the start up tasks. Learn more https://www.gitpod.io/docs/config-start-tasks/
+tasks:
+  - before: |
+      export GHCUP_INSTALL_BASE_PREFIX=/workspace
+      export BOOTSTRAP_HASKELL_NONINTERACTIVE=1
+      export BOOTSTRAP_HASKELL_MINIMAL=1
+      export CABAL_DIR=/workspace/.cabal
+      export STACK_ROOT=/workspace/.stack
+      curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh
+
+      # ensure that there is an HLS binary for the installed GHC version
+      /workspace/.ghcup/bin/ghcup install ghc 8.10.5 --set
+      /workspace/.ghcup/bin/ghcup install cabal
+
+      # Add ghcup binaries to the PATH since VSCode does not see 'source .ghcup/env'
+      pushd /usr/local/bin
+      sudo ln -s /workspace/.ghcup/bin/* /usr/local/bin
+      popd
+
+      # Fix the default Cabal config since VSCode does not see CABAL_DIR 
+      cabal update
+      mkdir ~/.cabal
+      cp /workspace/.cabal/config ~/.cabal/config
+    init: | 
+      cabal build --enable-tests      
+    command: | 
+      cabal build --enable-tests
+
+# List the ports to expose. Learn more https://www.gitpod.io/docs/config-ports/
+ports: []
+
+github:
+  prebuilds:
+    # enable for the master/default branch (defaults to true)
+    master: true
+    # enable for all branches in this repo (defaults to false)
+    branches: false
+    # enable for pull requests coming from this repo (defaults to true)
+    pullRequests: true
+    # enable for pull requests coming from forks (defaults to false)
+    pullRequestsFromForks: true
+    # add a "Review in Gitpod" button as a comment to pull requests (defaults to true)
+    addComment: false
+    # add a "Review in Gitpod" button to pull requests (defaults to false)
+    addBadge: false
+    # add a label once the prebuild is ready to pull requests (defaults to false)
+    addLabel: prebuilt-in-gitpod
+
+vscode:
+  extensions:
+    - "haskell.haskell"
+    - "justusadam.language-haskell"
+    - "usernamehw.errorlens"