Add CI job for testing every PR

.dockerignore

@@ -1,5 +1,6 @@
 .gitignore
 /.git
+/.github
 /tests
 /target
 /Dockerfile

.github/workflows/verify.yml

@@ -0,0 +1,52 @@
+name: Verify
+
+on:
+  pull_request:
+    branches: [main]
+  workflow_call:
+    inputs:
+      malachite_git_ref:
+        required: true
+        type: string
+        default: "8a9f3702eb41199bc8a7f45139adba233a04744a"
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    timeout-minutes: 5
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/cache/restore@v4
+        id: malachite-cache
+        with:
+          path: malachite
+          key: ${{ runner.os }}-${{ runner.arch }}-${{ inputs.malachite_git_ref }}
+      - if: ${{ steps.malachite-cache.outputs.cache-hit != 'true' }}
+        uses: actions/checkout@v4
+        with:
+          repository: farcasterxyz/malachite
+          ref: ${{ inputs.malachite_git_ref }}
+          path: malachite
+      - if: ${{ steps.malachite-cache.outputs.cache-hit != 'true' }}
+        working-directory: malachite/code
+        run: cargo build
+      - if: ${{ steps.malachite-cache.outputs.cache-hit != 'true' }}
+        uses: actions/cache/save@v4
+        id: malachite-cache
+        with:
+          path: malachite
+          key: ${{ runner.os }}-${{ runner.arch }}-${{ inputs.malachite_git_ref }}
+
+      - uses: actions/checkout@v4
+        with:
+          path: snapchain
+      - working-directory: snapchain
+        run: cargo build
+      - working-directory: snapchain
+        run: cargo test
+      - working-directory: snapchain
+        run: cargo fmt --all --check
+

README.md

@@ -2,6 +2,17 @@
 
 Prototype for the snapchain proposal
 
+## Development Notes
+
+🚨 **We are not accepting external PRs at this time** 🚨
+
+Presently, due to our current development velocity, we don't have time to review or discuss external PRs. Any PRs opened
+against the repo will be closed.
+
+We may accept external PRs at a later date, at which point this note will be removed.
+
+Thank you for your interest in the project!
+
 ## Prerequisites
 
 Before you begin, ensure you have the following installed:
@@ -15,7 +26,7 @@ Before you begin, ensure you have the following installed:
    ```
    git clone [email protected]:informalsystems/malachite.git
    cd malachite
-   git checkout 8a9f3702eb41199bc8a7f45139adba233a04744a
+   git checkout 8a9f3702eb41199bc8a7f45139adba233a04744a # Remember to update GitHub workflow when changing
    cd code && cargo build
    ```
 2. Then clone the snapchain repo and build it: