add docker build to ci

.github/workflows/rust.yml

@@ -50,3 +50,32 @@ jobs:
           CRATES_TOKEN: ${{ secrets.CRATES_TOKEN }}
         run: |
           cargo publish --package upid --token $CRATES_TOKEN --allow-dirty
+
+  docker:
+    needs: test
+    runs-on: ubuntu-latest
+    if: startsWith(github.ref, 'refs/tags/')
+    steps:
+      - uses: actions/checkout@v4
+      - uses: docker/setup-qemu-action@v3
+      - uses: docker/setup-buildx-action@v3
+      - uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Extract tag name
+        id: extract_tag
+        run: echo "RELEASE_TAG=${GITHUB_REF#refs/tags/}" >> $GITHUB_ENV
+      - name: Docker Buildx base image
+        env:
+          RELEASE_TAG: ${{ env.RELEASE_TAG }}
+        run: |
+          docker buildx build \
+            --platform linux/amd64,linux/arm64 \
+            --output "type=image,push=true" \
+            --tag "carderne/postgres-upid:16-${RELEASE_TAG}" \
+            --tag "carderne/postgres-upid:16" \
+            --tag "carderne/postgres-upid:latest" \
+            --cache-from "carderne/postgres-upid:latest" \
+            --cache-to type=inline \
+            .

README.md

@@ -15,20 +15,29 @@ UPID allows a prefix of up to **4 characters** (will be right-padded if shorter
 
 This is a UPID in Python:
 ```python
-upid("user")        # user_2accvpp5guht4dts56je5a
+upid("user")            # user_2accvpp5guht4dts56je5a
 ```
 
 And in Rust:
 ```rust
-UPID::new("user")  // user_2accvpp5guht4dts56je5a
+UPID::new("user")      // user_2accvpp5guht4dts56je5a
 ```
 
 And in Postgres too:
 ```sql
 CREATE TABLE users (id upid NOT NULL DEFAULT gen_upid('user') PRIMARY KEY);
 INSERT INTO users DEFAULT VALUES;
-SELECT id FROM users;
--- user_2accvpp5guht4dts56je5a
+SELECT id FROM users;  -- user_2accvpp5guht4dts56je5a
+
+-- this also works
+SELECT id FROM users WHERE id = 'user_2accvpp5guht4dts56je5a';
+```
+
+Plays nice with your server code too, no extra work needed:
+```python
+with psycopg.connect("postgresql://...") as conn:
+    res = conn.execute("SELECT id FROM users").fetchone()
+    print(res)          # user_2accvpp5guht4dts56je5a
 ```
 
 ## Specification