Use hydra instead of drone

.drone.yml

@@ -1,9 +0,0 @@
-kind: pipeline
-name: default
-type: exec
-
-steps:
-  - name: build
-    commands:
-      - nix build -L
-      - readlink -f result

flake.nix

@@ -164,7 +164,11 @@
 
               src = self;
 
-              buildPhase = "mkdocs build -d $out";
+              buildPhase = ''
+                mkdocs build -d $out
+                mkdir -p $out/nix-support
+                echo "doc wiki $out" >> $out/nix-support/hydra-build-products
+              '';
 
               installPhase = ''
                 mkdir -p $out/assets/fonts
@@ -188,5 +192,13 @@
           '');
         };
       };
+
+      # My hydra only has x86_64-linux builders
+      hydraJobs =
+        if builtins.elem system [ "x86_64-linux" ]
+        then {
+          build = packages.wiki;
+        }
+        else { };
     });
 }