Adding a block model and filter mentions from blocked users (fix #60)

db/migrate/20161003145426_create_blocks.rb

@@ -0,0 +1,12 @@
+class CreateBlocks < ActiveRecord::Migration[5.0]
+  def change
+    create_table :blocks do |t|
+      t.integer :account_id, null: false
+      t.integer :target_account_id, null: false
+
+      t.timestamps null: false
+    end
+
+    add_index :blocks, [:account_id, :target_account_id], unique: true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20161003142332) do
+ActiveRecord::Schema.define(version: 20161003145426) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -43,6 +43,14 @@ ActiveRecord::Schema.define(version: 20161003142332) do
     t.index ["username", "domain"], name: "index_accounts_on_username_and_domain", unique: true, using: :btree
   end
 
+  create_table "blocks", force: :cascade do |t|
+    t.integer  "account_id",        null: false
+    t.integer  "target_account_id", null: false
+    t.datetime "created_at",        null: false
+    t.datetime "updated_at",        null: false
+    t.index ["account_id", "target_account_id"], name: "index_blocks_on_account_id_and_target_account_id", unique: true, using: :btree
+  end
+
   create_table "favourites", force: :cascade do |t|
     t.integer  "account_id", null: false
     t.integer  "status_id",  null: false