auto assign PR authors and teams (#30455)

.github/team.json

+{
+  "teams": [
+    {
+      "name": "App Viz",
+      "label": ".Team/Viz 📊",
+      "members": [
+        "alxnddr",
+        "iethree",
+        "npfitz",
+        "EmmadUsmani",
+        "JesseSDevaney"
+      ]
+    },
+    {
+      "name": "Query Builder",
+      "label": ".Team/QueryBuilder 🧮",
+      "members": [
+        "ranquild",
+        "WiNloSt",
+        "deniskaber",
+        "oisincoveney",
+        "uladzimirdev"
+      ]
+    },
+    {
+      "name": "App BE",
+      "label": ".Team/Backend 🥞",
+      "members": ["dpsutton", "tsmacdonald", "qnkhuat", "calherries"]
+    },
+    {
+      "name": "Query Processor",
+      "label": ".Team/QueryProcessor 🛠️",
+      "members": [
+        "camsaul",
+        "kulyk",
+        "snoe",
+        "bshepherdson",
+        "john-metabase",
+        "metamben"
+      ]
+    },
+    {
+      "name": "Fun Police",
+      "label": ".Team/FunPolice 👮",
+      "members": ["noahmoss", "escherize", "adam-james-v"]
+    }
+  ]
+}

.github/workflows/auto-assign.yml

+name: Auto assign pull requests
+
+on:
+  pull_request:
+    types:
+      - opened
+
+jobs:
+  update_pr:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: tibdex/github-app-token@v1.6.0
+        id: generate-token
+        with:
+          app_id: ${{ secrets.METABASE_BOT_APP_ID }}
+          private_key: ${{ secrets.METABASE_BOT_APP_PRIVATE_KEY }}
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Assign author and their team. Returns true if team exists.
+        id: auto-assign
+        uses: actions/github-script@v6
+        with:
+          github-token: ${{ steps.generate-token.outputs.token }}
+          script: |
+            const fs = require('fs');
+            const teamConfig = JSON.parse(fs.readFileSync('.github/team.json', 'utf-8'));
+            const prAuthor = context.payload.pull_request.user.login;
+            const prNumber = context.payload.pull_request.number;
+
+            // Assign PR author
+            await github.rest.issues.addAssignees({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: prNumber,
+              assignees: [prAuthor]
+            });
+
+            const team = teamConfig.teams.find(t => t.members.includes(prAuthor));
+            if (!team) {
+              console.log('You are not assigned to any team. If you need one, update .github/team.json');
+              return false;
+            }
+
+            // Add team label
+            await github.rest.issues.addLabels({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: prNumber,
+              labels: [team.label]
+            });
+
+            return true;
+      - uses: actions/add-to-project@v0.5.0
+        if: ${{ fromJSON(steps.auto-assign.outputs.result) }}
+        with:
+          project-url: https://github.com/orgs/metabase/projects/50/views/1
+          github-token: ${{ steps.generate-token.outputs.token }}