Seperate out postgres tests and clarify postgres support (#1494)

* Clarifies the position on supporting Postgres and removes Postgres from the main test suite
* Closes #973

.github/workflows/sqlite.yml

@@ -0,0 +1,44 @@
+---
+name: CTFd SQLite CI
+
+on: [pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        python-version: ['3.6']
+        TESTING_DATABASE_URL: ['sqlite://']
+
+    name: Python ${{ matrix.python-version }}
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup python
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+          architecture: x64
+      - name: Install dependencies
+        run: |
+            python -m pip install --upgrade pip
+            python -m pip install -r development.txt
+            sudo yarn install --non-interactive
+            sudo yarn global add prettier@1.17.0
+
+      - name: Lint
+        run: make lint
+
+      - name: Test
+        run: |
+            sudo rm -f /etc/boto.cfg
+            make test
+        env:
+            AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
+            AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+
+      - name: Coverage
+        run: codecov
+