added friend_requests table

manifest

@@ -1,3 +1,4 @@
 sessions.sql
 users.sql
 sessions_api_v1.sql
+users_v1.sql

up/users_v1.sql

@@ -0,0 +1,11 @@
+-- friend requests
+CREATE TABLE friend_requests (
+    id VARCHAR(64) PRIMARY KEY DEFAULT uuid_generate_v4(),
+    user_id VARCHAR(64) REFERENCES users(id) ON DELETE CASCADE,
+    friend_id VARCHAR(64) REFERENCES users(id) ON DELETE CASCADE,
+    accepted BOOLEAN,
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+ALTER TABLE friend_requests ADD CONSTRAINT user_friend_request_uniqkey UNIQUE (user_id, friend_id);