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.
[FEATURE] Embedded host-meta and webfinger into gatewayd utilizing the new config initializers pattern

[TASK] bump patch of host-meta-plugin.

[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

[FIX] Update host-meta-plugin and bridge-payments-plugin version to point to updated versions

[FIX] Updated to conform to the latest gateway services protocol spec
[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
[FEATURE] Get and set last payment hash in database.

[FOLD] Use plain getColdWallet function.

[FOLD] Set current hash not previous hash.

[FOLD] Remove redundant lastHash if check.
[DOC] Release notes v3.30.0.
Merge branch 'release-3.30.0-rc1'
[TASK] Bump minor version.
[FIX] BodyParser requires extended option.
Merge pull request #392 from ripple/body-parser-extended-fix

[FIX] BodyParser requires extended option.
[FEATURE] replace async with bluebird, handle ripplerest responses
Merge pull request #394 from ripple/ripple-outgoing-error-handling

[FEATURE] replace async with bluebird, handle ripplerest responses
[FEATURE] Use api.ripple.com for REST by default.