The docs should have an example of how to create/use custom contracts

In general we need to have more step by step walk throughs of how to use Arc and Arc.js, and how to build on top of them, especially creating new voting machines, schemes and global constraints and deploying and using them.

The issue names no files or tests. Start by locating the existing Arc and Arc.js documentation and examples, then identify the entry points for creating, deploying, and using custom contracts. Done means the relevant workflows have step-by-step examples covering custom voting machines, schemes, and global constraints.

Written by the indexing model from the issue text.