Type mismatch when trying to add to custom seq

[PMunch]

It's a subtle bug, but essentially your object isn't mutable, so the sequence 
isn't mutable. The type error is because it's `seq[Terminal]` and `add` 
requires a `var seq[Terminal]`. Replacing `schematicConnect` with this works:
    
    
    proc schematicConnect(schematic: var Schematic, terminal: Terminal, node: 
Terminal): bool =
        for adjacencyList in schematic.mitems:
            if adjacencyList.terminal == terminal:
                adjacencyList.connections.add(node)
        for adjacencyList in schematic.mitems:
            if adjacencyList.terminal == node:
                adjacencyList.connections.add(terminal)
    
    
    Run