Update install.md

nconf throws the following expcetion:

    SyntaxError: Unexpected token '

change the single quotes to double quotes for the new line in the config/config.json
Merge pull request #365 from JavierGSanchez/patch-1

Update install.md
[DOC] Add gatewayd-admin doc
[FEATURE] Policy Engine determines policy and applies sequentially.
[FEATURE] Check if user_policy applies to an incoming payment.
[FEATURE] Check if invoice_policy applies to an incoming external payment.
[FEATURE] Apply no_policy if no applicable policy found.
[FEATURE] Check if bridge_policy applies to external payment.
[FEATURE] Determine which policy to apply using PolicyEngine
.
[FEATURE] Include host_meta plugin in config/initializers.
Update restart_gateway.js
[FEATURE] Add configs database table, migration and model.
[TASK] Move global logger to gatewayd.logger in /processes.
[TASK] bump patch of host-meta-plugin.
[FEATURE] Embedded host-meta and webfinger into gatewayd utilizing the new config initializers pattern
[FEATURE] Added sender to path on bridge quote link to conform to spec
[FEATURE] Added bridge payment status link to host meta and webfinger
[FEATURE] Added bridge payments to the initializers
[TASK] Update package name to "gatewayd"

Conflicts:
	package.json

[TEST] confirm all payments have txn_hash

[TEST] fixture for a valid transaction

[TEST] fixture for a valid transaction
[FIX] mark successful payments only after payment is confirmed