Update ci.yml

Author: ViralBShah

.github/workflows/ci.yml

@@ -1,4 +1,6 @@
 name: CI
+env:
+  JULIA_NUM_THREADS: 2
 on:
   pull_request:
     branches:
@@ -15,11 +17,11 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.5' # Replace this with the minimum Julia version that your package supports. E.g. if your package requires Julia 1.5 or higher, change this to '1.5'.
-          - '1' # Leave this line unchanged. '1' will automatically expand to the latest stable 1.x release of Julia.
-          - 'nightly'
+          - '1'
         os:
           - ubuntu-latest
+          - macos-latest
+          - windows-latest
         arch:
           - x64
     steps:
@@ -44,3 +46,25 @@ jobs:
       - uses: codecov/codecov-action@v1
         with:
           file: lcov.info
+  docs:
+    name: Documentation
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: julia-actions/setup-julia@v1
+        with:
+          version: '1'
+      - run: |
+          julia --project=docs -e '
+            using Pkg
+            Pkg.develop(PackageSpec(path=pwd()))
+            Pkg.instantiate()'
+      - run: |
+          julia --project=docs -e '
+            using Documenter: doctest
+            using Circuitscape
+            doctest(Circuitscape)' 
+      - run: julia --project=docs docs/make.jl
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          DOCUMENTER_KEY: ${{ secrets.DOCUMENTER_KEY }}