Added admin interface to manage channels and enabled plugins (#9)

* Added base admin login/logout flows

* Ignore local database

* Channel model

* Admin interface for channels and plugins

* Added database tests along with workflows

* Added some docstrings

* Ignore .coverage file

* Creating plugins docs WIP

* Documentation

* Black everything

* Some documentation

* Coverage for the plugins package as well

* DB Fixes

* Absolute FROM in Dockerfile

* Database and logging fixes

* Slack: Support private channels

* Added pre-commit

* black'd

* Fixed UserQuery.create

* Fixed ChannelPluginQuery.create exists call

* Added ChannelPlugin menu for debugging

* Ignore sqlite databases

* Updated contributing docs

.github/workflows/black.yaml

@@ -0,0 +1,27 @@
+name: Black
+
+on:
+  push:
+    branches: [ master, stable ]
+  pull_request:
+    branches: [ master, stable ]
+
+jobs:
+  black:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
+
+    - name: Install dependencies
+      run: |
+        pip install --upgrade pip
+        pip install black
+
+    - name: Black check
+      run: |
+        black --check butterrobot