Add Heroku deployment support

app.json

@@ -0,0 +1,91 @@
+{
+  "name": "Mastodon",
+  "description": "A GNU Social-compatible microblogging server",
+  "repository": "https://github.com/tootsuite/mastodon",
+  "logo": "https://github.com/tootsuite/mastodon/raw/master/app/assets/images/logo.png",
+  "env": {
+    "HEROKU": {
+      "description": "Leave this as true",
+      "value": "true",
+      "required": true
+    },
+    "LOCAL_DOMAIN": {
+      "description": "The domain that your Mastodon instance will run on (this can be appname.herokuapp.com or a custom domain)",
+      "required": true
+    },
+    "LOCAL_HTTPS": {
+      "description": "Will your domain support HTTPS? (Automatic for herokuapp, requires manual configuration for custom domains)",
+      "value": "false",
+      "required": true
+    },
+    "PAPERCLIP_SECRET": {
+      "description": "The secret key for storing media files",
+      "generator": "secret"
+    },
+    "SECRET_KEY_BASE": {
+      "description": "The secret key base",
+      "generator": "secret"
+    },
+    "SINGLE_USER_MODE": {
+      "description": "Should the instance run in single user mode? (Disable registrations, redirect to front page)",
+      "value": "false",
+      "required": true
+    },
+    "S3_ENABLED": {
+      "description": "Should Mastodon use Amazon S3 for storage? This is highly recommended, as Heroku does not have persistent file storage (files will be lost).",
+      "value": "true",
+      "required": false
+    },
+    "S3_BUCKET": {
+      "description": "Amazon S3 Bucket",
+      "required": false
+    },
+    "S3_REGION": {
+      "description": "Amazon S3 region that the bucket is located in",
+      "required": false
+    },
+    "AWS_ACCESS_KEY_ID": {
+      "description": "Amazon S3 Access Key",
+      "required": false
+    },
+    "AWS_SECRET_ACCESS_KEY": {
+      "description": "Amazon S3 Secret Key",
+      "required": false
+    },
+    "SMTP_SERVER": {
+      "description": "Hostname for SMTP server, if you want to enable email",
+      "required": false
+    },
+    "SMTP_PORT": {
+      "description": "Port for SMTP server",
+      "required": false
+    },
+    "SMTP_LOGIN": {
+      "description": "Username for SMTP server",
+      "required": false
+    },
+    "SMTP_PASSWORD": {
+      "description": "Password for SMTP server",
+      "required": false
+    },
+    "SMTP_DOMAIN": {
+      "description": "Domain for SMTP server. Will default to instance domain if blank.",
+      "required": false
+    }
+  },
+  "buildpacks": [
+    {
+      "url": "heroku/nodejs"
+    },
+    {
+      "url": "heroku/ruby"
+    }
+  ],
+  "scripts": {
+    "postdeploy": "bundle exec rails db:migrate && bundle exec rails db:seed"
+  },
+  "addons": [
+    "heroku-postgresql",
+    "heroku-redis"
+  ]
+}