Add an example for using auth for logging in

demo/src/app/views/login.zig

@@ -0,0 +1,38 @@
+const std = @import("std");
+const jetzig = @import("jetzig");
+const auth = @import("jetzig").auth;
+
+pub fn index(request: *jetzig.Request) !jetzig.View {
+    return request.render(.ok);
+}
+
+pub fn post(request: *jetzig.Request) !jetzig.View {
+    const Login = struct {
+        email: []const u8,
+        password: []const u8,
+    };
+
+    const params = try request.expectParams(Login) orelse {
+        return request.fail(.forbidden);
+    };
+
+    // Lookup the user by email
+    const query = jetzig.database.Query(.User).findBy(
+        .{ .email = params.email },
+    );
+
+    const user = try request.repo.execute(query) orelse {
+        return request.fail(.forbidden);
+    };
+
+    // Check that the password matches
+    if (try auth.verifyPassword(
+        request.allocator,
+        user.password_hash,
+        params.password,
+    )) {
+        try auth.signIn(request, user.id);
+        return request.redirect("/", .found);
+    }
+    return request.fail(.forbidden);
+}

demo/src/app/views/login/index.zmpl

@@ -0,0 +1,7 @@
+<form method="post" id="login">
+  <input type="email" name="email" placeholder="name@example.com">
+  <label for="email">Email address</label>
+  <input type="password" name="password" placeholder="Password">
+  <label for="paddword">Password</label>
+  <button type="submit" form="login">Sign in</button>
+</form>